UNDERWRITING AGREEMENT

                                                                     EXHIBIT 1.1

              CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES CORP.
                                    Depositor

          Commercial Mortgage Pass-Through Certificates, Series 2006-C4

                             UNDERWRITING AGREEMENT

                                                              September 21, 2006

CREDIT SUISSE SECURITIES (USA) LLC
Eleven Madison Avenue
New York, New York   10010

LASALLE FINANCIAL SERVICES, INC.
540 W. Madison Street, Suite 2800
Chicago, Illinois   60661

KEYBANC CAPITAL MARKETS, A DIVISION OF
MCDONALD INVESTMENTS INC.
127 Public Square
Cleveland, Ohio   44114-1306

BARCLAYS CAPITAL INC.
200 Park Avenue
New York, New York   10166

WACHOVIA CAPITAL MARKETS, LLC
301 South College Street
One Wachovia Center
Charlotte, North Carolina   28288

GREENWICH CAPITAL MARKETS, INC.
600 Steamboat Road
Greenwich, Connecticut   06830-7168

Ladies and Gentlemen:

      1. Introductory. Credit Suisse First Boston Mortgage Securities Corp., a
Delaware corporation (the "Depositor"), proposes to form one or more real estate
mortgage investment conduits (the "Trust"), which will issue securities entitled
Credit Suisse First Boston Mortgage Securities Corp. Commercial Mortgage
Pass-Through Certificates, (the "Certificates"), Series 2006-C4. Each
Certificate will evidence a fractional undivided, percentage interest or
beneficial interest in the Trust. The terms on which the Trust will issue the
Certificates will be specified in the Prospectus (as defined herein). The
property of the Trust will consist of a pool of 360 fixed rate mortgage loans,
secured by multifamily and commercial properties (collectively, the "Mortgage
Loans") that will be purchased by the Depositor from Column Financial, Inc. (the
"Column Mortgage Loan Seller"), LaSalle Bank National Association (the "LaSalle
Mortgage Loan Seller"), KeyBank National Association (the "KeyBank Mortgage Loan
Seller"), Barclays Capital Real Estate Inc. (the "Barclays Mortgage Loan
Seller") and NCB, FSB (the "NCB, FSB Mortgage Loan Seller" and together with the
Column Mortgage Loan Seller, the LaSalle Mortgage Loan Seller, the KeyBank
Mortgage Loan Seller and the Barclays Mortgage Loan Seller, the "Mortgage Loan
Sellers"), pursuant to those certain Mortgage Loan Purchase Agreements, each
dated as of September 1, 2006 (the "Mortgage Loan Purchase Agreements"), and
will be serviced by KeyCorp Real Estate Capital Markets, Inc. and NCB, FSB, each
as a Master Servicer of their respective group of Mortgage Loans as set forth in
the Pooling and Servicing Agreement (defined below) (collectively the "Master
Servicers"), and if and when necessary LNR Partners, Inc. or National Consumer
Cooperative Bank, each as Special Servicer of their respective group of mortgage
loans as set forth in the Pooling and Servicing Agreement (collectively the
"Special Servicers"), pursuant to that certain Pooling and Servicing Agreement
(the "Pooling and Servicing Agreement"), to be dated as of September 1, 2006, by
and among the Depositor, the Master Servicers, the Special Servicers, Wells
Fargo Bank, N.A., as trustee (the "Trustee"), and LaSalle Bank National
Association, as certificate administrator (the "Certificate Administrator") and
paying agent, and certain related property to be conveyed to the Trust by the
Depositor (the "Trust Fund"). The Mortgage Loans will be transferred to the
Trust, and the Certificates will be issued pursuant to the Pooling and Servicing
Agreement.

            The offering of the Certificates made pursuant to the Registration
Statement (as defined below) will be made through you as underwriters. This
Agreement provides for the sale of such Certificates to, and the purchase and
offering thereof by, you, as underwriters (the "Underwriters" and, individually,
an "Underwriter"). Schedule I shall specify the principal or notional balance of
each Class of the Certificates to be issued and any terms thereof not otherwise
specified in the Pooling and Servicing Agreement, the Classes of Certificates
subject to this Agreement, the price at which such Certificates are to be
purchased by the Underwriters from the Depositor, the aggregate amount of
Certificates to be purchased by you and the initial public offering price or the
method by which the price at which such Certificates are to be sold will be
determined. The offering of the Certificates will be governed by this Agreement.

            At or prior to the time when sales to purchasers of the Certificates
were first made, which was approximately 3:00 p.m. on September 21 , 2006 (the
"Time of Sale"), the Depositor had prepared the following information
(collectively, the "Rule 159 Information"): the Depositor's Free Writing
Prospectus dated September 8, 2006 (the cover page of which is attached hereto
as Annex A) to the Depositor's Prospectus dated September 8, 2006, the term
sheet dated September 8, 2006, relating to the Certificates, and each
"free-writing prospectus" (as defined pursuant to Rule 405 under the 1933 Act)
(a "Free Writing Prospectus") the first page of each of which is attached as
Annex B hereto. If, subsequent to the date of this Agreement, the Depositor and
the Underwriters determine that such information included an untrue statement of
material fact or omitted to state a material fact necessary in order to make the
statements therein, in the light of the circumstances under which they were
made, not misleading and terminate their old purchase contracts and enter into
new purchase contracts with investors in the Certificates, then "Rule 159
Information" will refer to the information conveyed to purchasers at the time of
entry into the first such new purchase contract, including any information that
corrects such material misstatements or omissions ("Corrective Information") and
"Time of Sale" will refer to the time and date on which such new purchase
contracts were entered into.

      2. Representations and Warranties of the Depositor.

            The Depositor represents and warrants to you as of the date hereof
as follows:

      (a) The Depositor has filed with the Securities and Exchange Commission
(the "Commission") a registration statement (No. 333-129918) on Form S-3 for the
registration of the Certificates under the Securities Act of 1933, as amended
(the "1933 Act"), which registration statement has become effective. The
Depositor proposes to file with the Commission pursuant to Rule 424(b) under the
1933 Act a supplement to the form of prospectus included in such registration
statement relating to the Certificates and the plan of distribution thereof.
Such registration statement, including the exhibits thereto and information that
is contained in the Prospectus (as defined below) and is deemed to be part of
and included in such registration statement, as such registration statement may
have been amended or supplemented at the date of the Prospectus, and including
the Prospectus, is hereinafter referred to as the "Registration Statement"; the
prospectus first required to be filed to satisfy the condition set forth in Rule
172(c) and pursuant to Rule 424(b) under the 1933 Act, is hereinafter referred
to as the "Base Prospectus"; such form of supplement to the Base Prospectus
relating to the Certificates, in the form first required to be filed to satisfy
the condition set forth in Rule 172(c) and pursuant to Rule 424(b) under the
1933 Act (including the Base Prospectus as so supplemented) is hereinafter
referred to as the "Prospectus Supplement"; and the Base Prospectus and the
Prospectus Supplement, together, are hereinafter referred to as the
"Prospectus." The conditions to the use of a registration statement on Form S-3
under the Act, as set forth in the General Instructions to Form S-3, and the
conditions of Rule 415 under the Act have been satisfied with respect to the
Registration Statement; and no other amendment to the Registration Statement
will be filed which shall have been reasonably disapproved by you promptly after
reasonable notice thereof. There is no request by the Commission for any further
amendment of the Registration Statement or the Prospectus or for any additional
information; the Commission has not issued any stop order suspending the
effectiveness of the Registration Statement and the Depositor is not aware of
any proceeding for that purpose having been instituted or threatened; and there
has been no notification with respect to the suspension of the qualification for
sale of the Certificates for sale in any jurisdiction or any proceeding for such
purpose having been instituted or threatened;

       (b) the Registration Statement (i) on its effective date and on the date
of the then most recently filed Prospectus Supplement conformed in all respects
to the requirements of the 1933 Act and the rules and regulations thereunder
(the "Rules and Regulations") and did not include any untrue statement of a
material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein not misleading and (ii) on the date
hereof will conform in all respects to the requirements of the 1933 Act and the
Rules and Regulations thereunder and will not include any untrue statement of a
material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein not misleading and the Prospectus on
the date hereof and on the Specified Delivery Date (as defined in Section 3
hereof) will conform in all respects to the requirements of the 1933 Act and the
Rules and Regulations thereunder and will not include any untrue statement of a
material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading; provided, however, that the
foregoing does not apply to statements in or omissions from either the
Registration Statement or the Prospectus to the extent based upon and in
conformity with (A) written information furnished to the Depositor by any
Underwriter specifically for use therein (the "Underwriter Information"), and
(B) the Mortgage Loan Seller's Information (collectively as defined in each of
the Indemnification Agreements, dated as of the date hereof (the
"Indemnification Agreements"), by and among the Depositor, each Mortgage Loan
Seller and each Underwriter);

      (c) There is no request by the Commission for any further amendment of the
Registration Statement or the Prospectus or for any additional information; the
Commission has not issued any stop order suspending the effectiveness of the
Registration Statement and the Depositor is not aware of any proceeding for that
purpose having been instituted or threatened; and there has been no notification
with respect to the suspension of the qualification for sale of the Certificates
for sale in any jurisdiction or any proceeding for such purpose having been
instituted or threatened;

      (d) The Rule 159 Information, at the Time of Sale, did not, and at the
Closing Date will not, contain any untrue statement of a material fact or omit
to state a material fact necessary in order to make the statements therein, in
the light of the circumstances under which they were made, not misleading;
provided that the Depositor makes no representation and warranty with respect to
(A) any statements or omissions made in reliance upon and in conformity with the
Underwriter Information or (B) any Mortgage Loan Seller Information contained in
or omitted from such Time of Sale Information. The parties acknowledge that none
of the Underwriters has furnished any Underwriter Information to the Depositor
expressly for use in the Rule 159 Information.

      (e) Other than the Prospectus, the Depositor (including its agents and
representatives other than the Underwriters in their capacity as such) has not
made, used, prepared, authorized, approved or referred to and will not make,
use, prepare, authorize, approve or refer to any "written communication" (as
defined in Rule 405 under the 1933 Act) that constitutes an offer to sell or
solicitation of an offer to buy the Certificates other than (i) any document not
constituting a prospectus pursuant to Section 2(a)(10)(a) of the 1933 Act or
Rule 134 under the 1933 Act, (ii) the Rule 159 Information, and (iii) each other
written communication of the Depositor or its agents and representatives
approved by the Underwriters either in writing in advance or in any other manner
mutually agreed by the Underwriters and the Depositor (each such communication
referred to in clause (ii) and this clause (iii) constituting an Issuer Free
Writing Prospectus (as defined in Section 8(b) hereof). Each such Issuer Free
Writing Prospectus complied or, if used after the date hereof, will comply, in
all material respects with the 1933 Act and the rules and regulations
promulgated thereunder, has been filed or will be filed in accordance with
Section 8 (to the extent required thereby) and did not at the Time of Sale, and
at the Closing Date will not, contain any untrue statements of a material fact
or (when read in conjunction with the other Rule 159 Information) omit to state
a material fact necessary in order to make the statements therein, in the light
of the circumstances under which they were made, not misleading; provided that
the Depositor makes no representation and warranty with respect to (i) any
statements or omissions made in reliance upon and in conformity with the
Underwriter Information or (ii) any Mortgage Loan Seller Information contained
in or omitted from any Issuer Free Writing Prospectus. The parties acknowledge
that none of the Underwriters has furnished any Underwriter Information to the
Depositor expressly for use in any Issuer Free Writing Prospectus.

      (f) the Depositor has been duly organized and is validly existing as a
corporation in good standing under the laws of the State of Delaware, with full
corporate power and authority to own its assets and conduct its business as
described in the Prospectus, is duly qualified as a foreign corporation in good
standing in all jurisdictions in which the ownership or lease of its property or
the conduct of its business requires such qualification, except where the
failure to be so qualified would not have a material adverse effect on the
Depositor, and is conducting its business so as to comply in all material
respects with the applicable statutes, ordinances, rules and regulations of the
jurisdictions in which it is conducting business;

      (g) the Pooling and Servicing Agreement, the Mortgage Loan Purchase
Agreements and the Certificates conform, or will conform as of the Specified
Delivery Date, to the description thereof contained in the Registration
Statement and the Prospectus; and the Certificates, on the date hereof, will
have been duly and validly authorized and, when such Certificates are duly and
validly executed by the Depositor or the Trustee, authenticated by the Trustee
and delivered in accordance with the Pooling and Servicing Agreement and
delivered and paid for as provided herein, will be validly issued and
outstanding and entitled to the benefits afforded by the Pooling and Servicing
Agreement;

      (h) the Depositor is not in violation of its certificate of incorporation
or by-laws or in default under any agreement, indenture or instrument the effect
of which violation or default would be material and adverse to the Depositor or
which violation or default would have a material adverse effect on the
performance by the Depositor of its obligations under this Agreement, the
Pooling and Servicing Agreement, the Certificates or any of the Mortgage Loan
Purchase Agreements; there are no actions or proceedings against, or
investigations of, the Depositor pending, or, to the knowledge of the Depositor,
threatened, before any court, administrative agency or other tribunal (i)
asserting the invalidity of this Agreement, the Pooling and Servicing Agreement,
any of the Mortgage Loan Purchase Agreements or the Certificates, (ii) seeking
to prevent the issuance of the Certificates or the consummation of any of the
transactions contemplated by this Agreement, (iii) which might materially and
adversely affect the performance by the Depositor of its obligations under, or
the validity or enforceability against the Depositor of, this Agreement, the
Pooling and Servicing Agreement, any of the Mortgage Loan Purchase Agreements or
the Certificates or (iv) seeking to affect adversely the federal income tax
attributes of the Certificates described in the Prospectus;

      (i) there has not been, and as of the Specified Delivery Date there will
not be, any material adverse change in the business operations, financial
condition, properties or assets of the Depositor since the date of its latest
audited financial statements which would have a material adverse effect on the
ability of the Depositor to perform its obligations under this Agreement, the
Pooling and Servicing Agreement or any of the Mortgage Loan Purchase Agreements;

      (j) there are no contracts, indentures or other documents of a character
required by the 1933 Act or by the rules and regulations thereunder to be
described or referred to in the Registration Statement or the Prospectus or to
be filed as exhibits to the Registration Statement which have not been so
described or referred to therein or so filed or incorporated by reference as
exhibits thereto;

      (k) the Depositor possesses all material licenses, certificates,
authorizations or permits issued by the appropriate state, federal or foreign
regulatory agencies or bodies necessary to conduct the business now operated by
it, and the Depositor has not received any notice of proceedings relating to the
revocation or modification of any such license, certificate, authorization or
permit which, singly or in the aggregate, if the subject of any unfavorable
decision, ruling or finding, would materially and adversely affect the
condition, financial or otherwise, or the earnings, business affairs or business
prospects of the Depositor;

      (l) the issue and sale of the Certificates and the compliance by the
Depositor with all of the provisions of the Certificates, each Mortgage Loan
Purchase Agreement, this Agreement and the Pooling and Servicing Agreement, and
the execution and delivery by the Depositor of this Agreement, the Pooling and
Servicing Agreement and the Mortgage Loan Purchase Agreements are within the
corporate power of the Depositor and have been, or will have been, duly
authorized by all necessary corporate action on the part of the Depositor; and
neither the execution and delivery by the Depositor of such instruments, nor the
consummation by the Depositor of the transactions herein or therein
contemplated, nor the compliance by the Depositor with the provisions hereof or
thereof, will (A) conflict with or result in a breach of, or constitute a
default under, any of the provisions of the certificate of incorporation or
by-laws of the Depositor, (B) conflict with any of the provisions of any law,
governmental rule, regulation, judgment, decree or order binding on the
Depositor or its properties, (C) conflict with any of the provisions of any
indenture, mortgage, contract or other instrument to which the Depositor is a
party or by which it is bound or (D) except as contemplated by the Pooling and
Servicing Agreement, result in the creation or imposition of any lien, charge or
encumbrance upon any of its property or assets pursuant to the terms of any such
indenture, mortgage, contract or other instrument;

      (m) this Agreement has been duly authorized, executed and delivered by the
Depositor;

      (n) on the Specified Delivery Date, the Pooling and Servicing Agreement
and the Mortgage Loan Purchase Agreements will have been duly authorized,
executed and delivered by the Depositor and will be valid and binding agreements
of the Depositor, enforceable against the Depositor in accordance with their
respective terms, except to the extent that enforcement thereof may be limited
by (1) bankruptcy, insolvency, reorganization, moratorium or other similar laws
now or hereafter in effect relating to creditors' rights generally and (2)
general principles of equity (regardless of whether enforceability is considered
in a proceeding at law or in equity);

      (o) all approvals, authorizations, consents, orders or other actions of
any person, corporation or other organization, or of any court, governmental
agency or body or official (except with respect to the state securities or "blue
sky" laws of various jurisdictions) required in connection with the valid and
proper authorization, issuance and sale of the Certificates pursuant to this
Agreement and the Pooling and Servicing Agreement have been or will be taken or
obtained on or prior to the Specified Delivery Date;

      (p) at the Specified Delivery Date, each of the Mortgage Loans will meet
the criteria for selection described in the Prospectus Supplement;

      (q) neither the Depositor nor the Trust Fund is, and neither the sale of
the Certificates in the manner contemplated by the Prospectus nor the activities
of the Trust Fund pursuant to the Pooling and Servicing Agreement will cause the
Depositor or the Trust Fund to be an "investment company" or under the control
of an "investment company" as such terms are defined under the Investment
Company Act of 1940, as amended (the "Investment Company Act"), and the Pooling
and Servicing Agreement is not required to be qualified under the Trust
Indenture Act of 1939, as amended (the "Trust Indenture Act");

      (r) at the time of the execution and delivery of the Pooling and Servicing
Agreement, the Depositor (A) except as disclosed in the Prospectus, will convey
to the Trustee, or cause to be conveyed to the Trustee, all of the Depositor's
right, title and interest in and to the Mortgage Loans being transferred to the
Trustee pursuant to the Pooling and Servicing Agreement, free and clear of any
lien, mortgage, pledge, charge, encumbrance, adverse claim or other security
interest (collectively "Liens") granted by or imposed upon the Depositor, (B)
will not have assigned to any person any of its right, title or interest in the
Mortgage Loans or in the Pooling and Servicing Agreement or the Certificates,
and (C) will have the power and authority to transfer or cause to be transferred
the Mortgage Loans to the Trustee and to sell the Certificates to the
Underwriters. Upon execution and delivery of the Pooling and Servicing Agreement
by the Trustee, the Trustee will have acquired ownership of all of the
Depositor's right, title and interest in and to the Mortgage Loans except to the
extent disclosed in the Prospectus, and upon delivery to the Underwriters of the
Certificates pursuant hereto, each Underwriter will have good title to the
Certificates purchased by such Underwriter, in each case free of Liens granted
by or imposed upon the Depositor;

      (s) under generally accepted accounting principles and for federal income
tax purposes, the Depositor will report the transfer of the Mortgage Loans to
the Trustee in exchange for the Certificates and the sale of the Certificates to
the Underwriters pursuant to this Agreement as a sale of the interest in the
Mortgage Loans evidenced by the Certificates. The consideration received by the
Depositor upon the sale of the Certificates to the Underwriters will constitute
reasonably equivalent value and fair consideration for the Certificates. The
Depositor will be solvent at all relevant times prior to, and will not be
rendered insolvent by, the sale of the Certificates to the Underwriters. The
Depositor is not selling the Certificates to the Underwriters with any intent to
hinder, delay or defraud any of the creditors of the Depositor;

      (t) at the Specified Delivery Date, the respective Classes of Certificates
shall have been assigned ratings no lower than those set forth in Schedule I
hereto by the nationally recognized statistical rating organizations identified
in Schedule I hereto;

      (u) any taxes, fees and other governmental charges in connection with the
execution, delivery and issuance of this Agreement, the Pooling and Servicing
Agreement and the Certificates payable by the Depositor (other than income
taxes) have been paid or will be paid at or prior to the Specified Delivery
Date; and

      (v) the Depositor is not, and on the date on which the first bona fide
offer of the Certificates is made will not be, an "ineligible issuer," as
defined in Rule 405 under the 1933 Act.

      3. Purchase, Sale and Delivery of Certificates. Delivery of and payment
for the Certificates will be made at such place and at such time as shall be
specified in Schedule I or at such other time thereafter as set forth in
Schedule I or as you and the Depositor shall agree upon, each such time being
hereinafter referred to as a "Specified Delivery Date." Delivery of such
Certificates shall be made by the Depositor to the Underwriters against payment
of the purchase price specified in Schedule I in same day funds wired to such
bank as may be designated by the Depositor, or by such other manner of payment
as may be agreed upon by the Depositor and you. Unless otherwise provided for,
the Certificates to be so delivered will be in definitive, fully registered
form, in such denominations and registered in such names as you request, and
will be made available through the facilities of The Depository Trust Company,
or otherwise as you may request.

      4. Offering by Underwriters.

      (a) It is understood that the Underwriters propose to offer the
Certificates subject to this Agreement for sale to the public as set forth in
the Prospectus.

      (b) Each Underwriter represents, warrants and agrees that: (i) it has not
sold or offered the Certificates in the United Kingdom, and it has not delivered
or communicated the Prospectus or any other invitation or inducement to buy or
participate in the Certificates in the United Kingdom, except to persons who (A)
have professional experience of participating in unregulated collective
investment schemes and of matters relating to investments falling within both
Article 14(5) of the Financial Services and Markets Act 2000 (Promotion of
Collective Investment Schemes) (Exemptions) Order 2001 (the "CIS Order") and
Article 19(5) of the Financial Services and Markets Act (Financial Promotion)
Order 2001 (the "FP order") or (B) fall within Article 22(2)(a) through (d)
("high net worth companies, unincorporated associations, etc.") of the CIS Order
and Article 49(2)(a) though (d) of the FP Order; and (ii) it has complied and
will comply with all applicable provisions of the Financial Services and Markets
Act 2000 with respect to anything done by it in relation to the Certificates in,
from or otherwise involving the United Kingdom.

      5. Covenants of the Depositor. The Depositor covenants and agrees with you
that:

      (a) the Depositor has prepared and/or shall prepare a Prospectus
Supplement setting forth the amount of Certificates covered thereby and the
terms thereof not otherwise specified in the Base Prospectus, the price at which
such Certificates are to be purchased by the Underwriters from the Depositor,
either the initial public offering price or the method by which the price at
which such Certificates are to be sold will be determined, the selling
concessions and reallowances, if any, and such other information as you and the
Depositor deem appropriate in connection with the offering of such Certificates,
but the Depositor shall not file any amendments to the Registration Statement as
in effect with respect to the Certificates, or any amendments or supplements to
the Prospectus, unless it has first delivered copies of such amendments or
supplements to you and given you a reasonable opportunity to review the same or
if you have reasonably objected thereto promptly after receipt thereof; the
Depositor shall immediately advise you or your counsel (i) when notice is
received from the Commission that any post-effective amendment to the
Registration Statement has been filed or has become or will become effective or
any supplement to the Prospectus or any amended Prospectus, in each case
relating to the Certificates specified in Schedule I has been filed and will
furnish you with copies thereof, (ii) of any request by the Commission for any
amendment of the Registration Statement or the Prospectus or for any additional
information relating to the Certificates and (iii) of any order or communication
suspending or preventing, or threatening to suspend or prevent, the offer and
sale of the Certificates or of any proceedings or examinations that may lead to
such an order or communication, whether by or of the Commission or any authority
administering any state securities or "blue sky" law, as soon as the Depositor
is advised thereof, and shall use its best efforts to prevent the issuance of
any such order or communication and to obtain as soon as possible its lifting,
if issued;

      (b) if, at any time when the Prospectus is required to be delivered under
the 1933 Act, any event occurs as a result of which the Prospectus as then
amended or supplemented would include any untrue statement of a material fact or
omit to state any material fact necessary to make the statements therein, in
light of the circumstances under which they were made, not misleading, or if it
is necessary at any time to amend or supplement the Prospectus to comply with
the 1933 Act or the Rules and Regulations, the Depositor shall prepare and file
with the Commission, an amendment or supplement that will correct such statement
or omission or an amendment that will effect such compliance;

      (c) the Depositor shall make generally available to the holders of the
Certificates (the "Certificateholders"), in each case as soon as practicable,
earning statements covering (i) a period of 12 months beginning not later than
the first day of the related Trust's fiscal quarter next following the effective
date of the Registration Statement and (ii) a period of 12 months beginning no
later than the first day of the Trust's fiscal quarter next following the date
hereof which will satisfy the provisions of Section 11(a) of the 1933 Act and
Rule 158 of the Commission with respect to the Certificates. The Depositor shall
cause the Trustee to furnish or make available, within a reasonable time after
the end of each calendar year, to each holder of a Certificate at any time
during such year, such information as the Depositor deems necessary or desirable
to assist Certificateholders in preparing their federal income tax returns;

      (d) the Depositor shall furnish to you copies of the Registration
Statement, the Prospectus, and all amendments and supplements to such documents
relating to the Certificates, in each case as soon as available and in such
quantities as you reasonably request as long as the Depositor is required to
deliver the Prospectus under the 1933 Act in connection with the sale of the
Certificates; provided that any such documents requested by you on a date that
is more than nine (9) months after September 28, 2006 (the "Closing Date") shall
be provided at your expense;

      (e) the Depositor shall arrange for the qualification of the Certificates
for sale and the determination of their eligibility for investment under the
laws of such jurisdictions as you designate and shall continue such
qualifications in effect so long as required for the distribution; provided,
however, that neither the Depositor nor the Trust shall be required to qualify
to do business in any jurisdiction where it is now not qualified or to take any
action which would subject it to general or unlimited service of process in any
jurisdiction in which it is now not subject to service of process;

      (f) the Depositor shall, while the Certificates are outstanding;

            (i) furnish to you, as soon as available, copies of all reports
filed with the Commission and copies of each notice published or mailed to
holders of the Certificates pursuant to the Pooling and Servicing Agreement; and

            (ii) furnish to you such other information with respect to the Trust
or its financial condition or results of operations, as you may reasonably
request, including but not limited to information necessary or appropriate to
the maintenance of a secondary market in the Certificates; and

      (g) as between itself and the Underwriters, the Depositor will pay all
expenses incidental to the performance of its obligations under this Agreement,
including without limitation (i) expenses of preparing, printing and reproducing
the Prospectus (including any amendments thereof and supplements thereto), the
Pooling and Servicing Agreement and the Certificates, (ii) the fees charged by
Fitch, Inc, ("Fitch"), Standard & Poor's Ratings Services, a division of The
McGraw-Hill Companies, Inc. ("S&P") and Moody's Investors Service, Inc.
("Moody's" and together with Fitch and S&P, the "Rating Agencies") for rating
the Certificates, (iii) the fees and expenses of the Trustee, and any agent of
the Trustee and the fees and disbursements of counsel for the Trustee in
connection with the Pooling and Servicing Agreement and the Certificates, and
(iv) all other costs and expenses incidental to the performance by the Depositor
of its obligations hereunder that are not otherwise specifically provided for in
this subsection. It is understood that, except as provided in this subsection
(g) and in Section 10 below, each Underwriter will pay all of its own expenses
including all out-of-pocket and/or internally allocated costs and expenses
incurred by them in connection with the transaction herein contemplated,
including, without limitation, fees and expenses of their counsel, any transfer
taxes on the Certificates and the expenses of any advertising of the offering of
the Certificates made by the Underwriters; and

      (h) during the period when a prospectus is required by law to be delivered
in connection with the sale of the Certificates pursuant to this Agreement, the
Depositor shall file, or cause the Trustee to file on behalf of the Trust, on a
timely and complete basis, all documents that are required to be filed by the
related Trust with the Commission pursuant to Sections 13, 14 or 15(d) of the
Securities Exchange Act of 1934, as amended (the "Exchange Act").

      6. Conditions to the Obligations of the Underwriters. The obligations of
the Underwriters to purchase and pay for the Certificates subject to this
Agreement will be subject to