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                                                                    EXHIBIT 10.1


                                 March 31, 1999



MS Acquisition Corp.
24331 Sherwood
Centerline, MI 48015

                        RE:     $10,000,000 REVOLVING CREDIT

Gentlemen:

        The terms and conditions under which NBD Bank (the "Bank") may make
loans to MS Acquisition Corp., a Delaware corporation (the "Company"), are as
follows:

        1.      Definitions.  As used herein the following terms shall have the
following respective meanings:

                "Aetna" shall mean Aetna Industries, Inc., a Delaware
corporation.

                "Aetna Holdings" shall mean Aetna Holdngs, Inc., a Delaware
corporation.

                "Business Day" shall mean a day other than a Saturday, Sunday or
other day on which the Bank is not open to the public for carrying on
substantially all of its banking functions.

                "Capital Stock" shall mean (i) in the case of any corporation,
all capital stock and any securities exchangeable for or convertible into
capital stock, (ii) in the case of an association or business entity, any and
all shares, interests, participations, rights or other equivalents (however
designated) of corporate stock in or to such association or entity, (iii) in the
case of a partnership or limited liability company, partnership or membership
interests (whether general or limited) and (iv) any other interest or
participation that confers on a Person the right to receive a share of the
profits and losses of, or distribution of assets of, the issuing Person, and
including, in all of the foregoing cases described in clauses (i), (ii), (iii)
or (iv), any warrants, rights or other options to purchase or otherwise acquire
any of the interests described in any of the foregoing cases.

                "Commitment" shall have the meaning ascribed thereto in Section
2.

                "Debt" of any person shall mean, as of any date (a) all
obligations of such person for borrowed money, (b) all obligations of such
person as lessee under any capital lease, (c) all obligations which are secured
by any Lien existing on any asset or property of such person whether or not the
obligation secured thereby shall have been assumed by such person, provided,
however, that Debt under this clause (c) shall not include indebtedness or
obligations secured by the interest of any lessor of real property in which such
person has a leasehold interest, as long as such indebtedness or obligation is
solely the indebtedness or obligation of such lessor or a third party and not of
such person, (d) the unpaid purchase price for goods, property or services
acquired by such person, except for trade accounts payable and similar unsecured
obligations arising in the ordinary course of business that are not materially
past due, (e) all liabilities of such person in respect of unfunded liabilities
under any pension plan of such person or of or for which such person is liable,
(f) all obligations of such person in respect of any interest






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rate or currency swap, rate cap or other similar transaction (valued in an
amount equal to the highest termination payment, if any, that would be payable
by such person upon termination for any reason on the date of determination),
and (g) all obligations of others similar in character to those described in
clauses (a) through (f) of this definition for which such person is contingently
liable, as obligator, guarantor, surety or in any other capacity, or in respect
of which obligations such person assures a creditor against loss or agrees to
take any action to prevent any such loss (other than endorsements of negotiable
instruments for collection in the ordinary course of business), including
without limitation all reimbursement obligations of such person in respect of
letters of credit, surety bonds or similar obligations and (h) all obligations
of such person to advance funds to, or to purchase assets, property or services
from, any other person in order to maintain the financial condition of such
other person.

                "Dollars" and "$" shall mean the lawful money of the United
States of America.

                "Eurodollar Business Day" shall mean, with respect to any
Eurodollar Rate Loan, a day which is both a Business Day and a day on which
dealings in Dollar deposits are carried out in the London interbank market.

                "Eurodollar Interest Period" shall mean, with respect to any
Eurodollar Rate Loan, the period commencing on the day such Eurodollar Rate Loan
is made or converted to a Eurodollar Rate Loan and ending on the day which is
one or two months thereafter, as the Company may elect, and each subsequent
period commencing on the last day of the immediately preceding Eurodollar
Interest Period and ending on the day which is one or two months thereafter, as
the Company may elect, provided, however, that (a) any Eurodollar Interest
Period which commences on the last Eurodollar Business Day of a calendar month
(or on any day for which there is no numerically corresponding day in the
appropriate subsequent calendar month) shall end on the last Eurodollar Business
Day of the appropriate subsequent calendar month, (b) each Eurodollar Interest
Period which would otherwise end on a day which is not a Eurodollar Business Day
shall end on the next succeeding Eurodollar Business Day or, if such next
succeeding Eurodollar Business Day falls in the next succeeding calendar month,
on the next preceding Eurodollar Business Day, and (c) no Eurodollar Interest
Period shall be permitted which would end after the Termination Date.

                "Eurodollar Rate" shall mean, with respect to any Eurodollar
Rate Loan and the related Eurodollar Interest Period, the per annum rate that is
equal to the sum of:

                        (a)     250 basis points, plus

                        (b)     the rate per annum obtained by dividing (i) the
per annum rate of interest at which deposits in Dollars for such Eurodollar
Interest Period and in an aggregate amount comparable to the amount of such
Eurodollar Rate Loan to be made hereunder are offered to the Bank by other prime
banks in the London interbank market at approximately 11:00 a.m. London time on
the second Eurodollar Business Day prior to the first day of such Eurodollar
Interest Period by (ii) an amount equal to one minus the stated maximum rate
(expressed as a decimal) of all reserve requirements (including, without
limitation, any marginal, emergency, supplemental, special or other reserves)
that are specified on the first day of such Eurodollar Interest Period by the
Board of Governors of the Federal Reserve System (or any successor agency
thereto) for determining the maximum reserve requirement with respect to
eurocurrency funding (currently referred to as "Eurocurrency liabilities" in
Regulation D of such Board) maintained by a member bank of such System; all as
conclusively determined by the Bank, such sum to be rounded up, if necessary, to
the nearest whole multiple of one one-hundredth of one percent (1/100 of 1%).

                "Eurodollar Rate Loan" shall mean any Loan which bears interest
at the Eurodollar Rate.



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                "Event of Default" shall mean any of the events or conditions
described in paragraph 9.

                "Federal Funds Rate" shall mean the per annum rate determined by
the Bank from time to time as the opening Federal Funds Rate paid or payable by
the Bank in its regional Federal Funds market for overnight borrowings from
other banks.

                "Floating Rate" shall mean the per annum rate equal to the
greater of (a) one percent (1%) per annum plus the Federal Funds Rate in effect
from time to time, or (b) the Prime Rate in effect from time to time; which
Floating Rate shall change simultaneously with any change in such Prime Rate or
Federal Funds Rate.

                "Generally Accepted Accounting Principles" shall mean generally
accepted accounting principles applied on a basis consistent with that reflected
in the most recent financial statements of the Company submitted to the Bank
prior to the date hereof.

                "Lien" shall mean any pledge, assignment, hypothecation,
mortgage, security interest, deposit arrangement, option, conditional sale or
title retaining contract, sale and leaseback transaction, lessor's or lessee's
interest under any lease, subordination of any claim or right, or any other type
of lien, charge or encumbrance.

                "Loan" shall mean any borrowing pursuant hereto.

                "Loan Documents" shall mean this letter agreement, the Note, the
Security Documents and all other agreements and documents executed pursuant
hereto at any time, in each case as amended or modified from time to time.

                "Material Adverse Effect" shall mean a material adverse effect
on (a) the business, assets, operations or condition (financial or otherwise) of
the Company and its Subsidiaries on a consolidated basis, (b) the ability of the
Company to perform its obligations under any Loan Document, or (c) the validity
of enforceability of any Loan Document or the rights or remedies of the Bank
under any Loan Document.

                "Net Worth" shall mean, as of any date, the amount of any
capital stock, paid in capital and similar equity accounts plus (or minus in the
case of a deficit) the capital surplus and retained earnings of any Person, all
in accordance with Generally Accepted Accounting Principles.

                "Note" shall mean the demand promissory note of the Company
evidencing the Loans, in the form annexed hereto as Exhibit A, as amended or
modified from time to time and together with any promissory note or notes issued
in exchange or replacement therefor.

                "Overdue Rate" shall mean, with respect to principal and other
amounts payable by the Company hereunder (other than interest), a rate per annum
that is equal to the sum of two percent (2%) per annum plus the Floating Rate.

                "Person" or "person" shall include an individual, a corporation,
an association, a partnership, a trust or estate, a joint stock company, an
unincorporated organization, a joint venture, a trade or business (whether or
not incorporated), a government (foreign or domestic) and any agency or
political subdivision thereof, or any other entity.

                "Prime Rate" shall mean the per annum rate announced by the Bank
from time to time as its "prime rate" (it being acknowledged that such announced
rate may not necessarily be the lowest rate

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charged by the Bank to any of its customers), which Prime Rate shall change
simultaneously with any change in such announced rate.

                "Prime Rate Loans" shall mean any Loan which bears interest at
the Prime Rate.

                "Security Documents" shall mean each pledge agreement and other
collateral document executed in connection herewith which grants a lien or
security interest and all other agreements and documents executed pursuant
thereto at any time, in each case as amended or modified from time to time.

                "SOFEDIT" shall mean Societe Financiere d' etudes de
Developpement Industrial et Technologique, a French societe anonyme.

                "Subsidiary" of any person shall mean any other person (whether
now existing or hereafter organized or acquired) in which (other than directors
qualifying shares required by law) at least a majority of the securities or
other ownership interests of each class having ordinary voting power or
analogous right (other than securities or other ownership interests which have
such power or right only by reason of the happening of a contingency), at the
time as of which any determination is being made, are owned, beneficially and of
record, by such person or by one or more of the other Subsidiaries of such
person or by any combination thereof. Unless otherwise specified, reference to
"Subsidiary" shall mean a Subsidiary of the Company.

                "Termination Date" shall mean the earliest to occur of (a) July
30, 1999, (b) the completion of any initial public offering by the Company or
(b) the date the Loans are accelerated by the Bank pursuant to Section 9.



        2.      Loans.

                (a) The Bank agrees, subject to the terms and conditions of this
agreement, to make Loans to the Company, from time to time from and including
the effective date of this letter to but excluding the Termination Date, not to
exceed $10,000,000 in aggregate principal amount at any time outstanding (the
commitment to make Loans in such amount and subject to such terms and conditions
defined herein as the "Commitment"). The Loans shall be used to make equity
contributions or, if permitted, subordination loans to Aetna. The Loans shall be
evidenced by the Note, payable on the Termination Date. The Company may at any
time voluntarily prepay all or any part of the Loans outstanding at such time
(including any interest payable thereon), without premium or penalty, provided
that any Eurodollar Rate Loan may not be prepaid prior to the end of the
Eurodollar Interest Period with respect thereto.

                (b) The Company agrees to pay to the Bank a commitment fee on
the daily average unused amount of the Commitment, for the period from the date
hereof to but excluding the Termination Date, at a rate equal to one half of one
percent (1/2%) per annum. Accrued commitment fee shall be payable on the last
Business Day of each month and on the Termination Date.

                (c) Interest shall be payable on the Loans prior to the
Termination Date at the Prime Rate or the Eurodollar Rate, as elected by the
Company hereunder. Interest shall be payable after the Termination Date on
demand by the Bank at the Overdue Rate. Unless earlier payment is required
hereunder, interest will be payable on the last day of each month with respect
to Prime Rate Loans and the last day of the relevant Eurodollar Interest Period
with respect to all Eurodollar Rate Loans and on the Termination Date.



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                (d) The Company shall give the Bank a verbal request, followed
immediately by a written request if required by the Bank, for each requested
Loan not later than 11:00 a.m. Detroit time (or such later time agreed to by the
Bank) on the Business Day such Loan is requested to be made if such Loan is a
Prime Rate Loan and on the date three Eurodollar Business Days prior to the date
such Loan is requested to be made if such Loan is a Eurodollar Rate Loan. Each
request for a Eurodollar Rate Loan shall be in a minimum amount of $1,000,000
and in integral multiples thereof, and shall also specify the allowable
Eurodollar Interest Period with respect thereto. The Bank may rely on all verbal
requests from any officer or other authorized person of the Company. Each
request for a Loan shall constitute a representation by the Company, and it is a
condition precedent to obtaining a Loan, that both before and after giving
effect to such Loan all the representations and warranties contained in Section
7 hereof are true and accurate on the date each Loan is to be made as if made on
and as of such date and that no Event of Default, or event or condition which
may become an Event of Default after notice or lapse time or both, has occurred
and is continuing.

                (e) The Company may elect to continue a Eurodollar Rate Loan as
a Eurodollar Rate Loan, or may elect to convert a Prime Rate Loan to a
Eurodollar Rate Loan, in each case by giving written request therefor, or a
verbal request followed immediately by a written request, not later than 11:00
a.m. Detroit time three Eurodollar Business Days prior to the date such
continuation or conversion is requested, provided that an outstanding Eurdollar
Rate Loan may only be continued on the last day of the then current Eurodollar
Interest Period with respect to such Loan and provided, further, if a
continuation of a Loan as, or conversion of a Loan to, a Eurodollar Rate Loan is
requested, such request shall also specify the Eurodollar Interest Period to be
applicable thereto. If the Company shall not deliver such a notice with respect
to any Eurodollar Rate Loan, the Company shall be deemed to have elected to
convert such Loan on the last day of the then current Eurodollar Interest Period
with respect to such Loan to a Prime Rate Loan.

        3.      Increased Costs; Limitations on Requests. The Company agrees to
(a) reimburse the Bank for any increase in cost to the Bank of making or
maintaining the Loans hereunder, or any reduction in any sum receivable
hereunder by the Bank due to any change in any applicable law, treaty, rule or
regulation (whether domestic or foreign) now or hereafter in effect (including
without limitation the Federal Deposit Insurance Act) or any interpretation or
administration thereof by any governmental authority or compliance by the Bank
with any request or directive of any such authority (whether or not having the
force of law), including, without limitation, in the event any of the foregoing
(i) affect the basis of taxation of payments to the Bank of any amounts payable
by the Company pursuant to this agreement, (ii) impose, modify or deem
applicable any insurance assessment or reserve, special deposit or similar
requirement against assets of, deposits with or for the account of, or credit
extended by the Bank, or (iii) affect the amount of capital required or expected
to be maintained by the Bank or its parent bank holding company, and (b)
indemnify the Bank for any and all losses the Bank may incur if the Company
makes any payment of principal with respect to any Eurodollar Rate Loan on any
date other than the last day of a Eurodollar Interest Period applicable thereto
or if the Company fails to borrow any Loan after notice requesting such Loan has
been given to the Bank. A detailed statement as to the amount of such increased
cost or reduced sum receivable, prepared in good faith and submitted by the Bank
to the Company, shall be conclusive and binding for all purposes absent manifest
error in computation. The Company further agrees that it may not elect the
Eurodollar Rate if it is impracticable, unlawful or impossible for any reason
for the Bank to make or maintain a Eurodollar Rate Loan and, if it is unlawful
or impossible for the Bank to maintain an outstanding Eurodollar Rate Loan, such
Loan shall be immediately due and payable, together with accrued interest and
any amount specified herein on the last day of the then current Eurdollar
Interest Period applicable to such Loan if the Bank may lawfully continue to
maintain such Loan to such day or immediately if the Bank may not continue to
maintain such Loan to such day.



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        4.       Conditions of Loans. On or before the date hereof, the Company
shall furnish to the Bank the Note duly executed and on or before the date ten
days after the date hereof the Company shall furnish to the Bank the following
documents, each in form and substance reasonably satisfactory to the Bank:

                (a) Certified copies of all charter documents of the Company,
including those evidencing corporate action with respect to the Loan Documents
and the Loans hereunder, as the Bank shall request.

                (b) Security Documents duly executed by the Company and such
other parties as may be required by the Bank in order to grant a first priority,
enforceable pledge of 64% of the Capital Stock of SOFEDIT and of 100% of the
Capital Stock of Aetna Holdings and Aetna, together with such original stock
certificates and other certificates and documents as may be required by the Bank
in connection therewith.

                (c) Certified resolutions and legal opinions to the extent
required by the Bank, each in form and substance satisfactory to the Bank.

                (d) Such other documents and agreements reasonably requested by
the Bank.

        5.      Affirmative Covenants. Until the expiration of this agreement
and thereafter until payment in full of all Debt under the Loan Documents of the
Company to the Bank and, the performance of all other obligations of the Company
under this agreement or otherwise owing by the Company to the Bank under any
other present or future agreement, the Company agrees that:

                (a) It shall furnish or cause to be furnished to the Bank the
following financial statements, information and certificates, each in form and
substance reasonably satisfactory to the Bank, at the times indicated:

                        (i)  Within 45 days after the end of each fiscal quarter
of the Company, the balance sheet of the Company as of the end of such quarter,
and the related statements of income and cash flow for such quarter, unaudited
but certified as correct in all material respects (subject to year-end
adjustments) by an officer of the Company.

                        (ii) Within 90 days after the end of each fiscal year of
the Company, a customary audit report of the Company for such fiscal year,
including the balance sheet of the Company as of the end of such fiscal year and
the related statements of income and cash flow of the company for the fiscal
year then ended, prepared by independent certified public accountants of
recognized standing.

                        (iii) Promptly, and in any event within three Business
Days after becoming aware thereof, written notice of the occurrence of any Event
of Default hereunder.

                        (iv) Promptly, such other information as the Bank may
reasonably request. Without limiting the foregoing, the Company agrees, upon the
reasonable request of the Bank, to permit the Bank or any of its agents or
representatives, upon reasonable notice and during normal business hours, to
examine and make copies of the records and books of account, and visit the
properties of, the Company and to discuss the affairs, finances and accounts of
the Company with its directors, officers, employees and auditors.


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                (b) It shall comply in all material respects with all applicable
laws, rules, regulations and orders of any governmental authority, whether
federal, state, local or foreign, including without limitation all environmental
laws, do or cause to be done all things necessary to preserve and keep in full
force and effect its legal existence and it rights, licenses and permits
material to the conduct of its businesses, and maintain, preserve and protect
all property material to the conduct of its business and maintain in full force
and effect insurance with responsible and reputable insurance companies or
associations in such amounts and on such terms and conditions as is typically
carried by companies engaged in similar businesses and owning similar
properties. The Company further agrees to deliver such Security Documents and
other agreements and legal opinions as may be required to grant a first priority
lien and security interests on 100% of the Capital Stock of each domestic
Subsidiary of the Company now or hereafter formed and 64% of the Capital Stock
of each foreign Subsidiary directly owned by the Company now or hereafter
formed.

        6.      Negative Covenants. Until the expiration of this agreement and
thereafter until payment in full of all Debt under the Loan Documents of the
Company owing to the Bank and, the performance of all other obligations of the
Company under this agreement, the Company agrees that it shall not:

                (a) Create, incur or suffer to exist any Liens on any of the
assets, rights, revenues or property, real, personal or mixed, tangible or
intangible, whether now owned or hereafter acquired, of the Company, other than
the following: (i) Liens for taxes not delinquent or for taxes being contested
in good faith by appropriate proceedings; (ii) Liens created and maintained in
the ordinary course of business which are not material in the aggregate and
which would not have a material adverse effect on the business or operations of
the Company; (iii) pledges or deposits required under law pursuant to workers
compensation laws, unemployment insurance laws or similar legislation; (iv)
Liens created in favor of the Bank; (v) deposits of money securing statutory
obligations of the Company; (vi) workers', mechanics' or similar liens arising
in the ordinary course of business, so long as such liens attach only to
equipment, fixtures and or real estate, for sums not yet due and payable or
which are being contested in good faith by appropriate proceedings or which are
in existence for less than thirty (30) days after the Company receives notice of
such lien; (vii) deposits securing, or in lieu of, surety, appeal or customs
bonds in proceedings in which the Company is a party, (viii) liens affecting
real property which constitute minor survey exceptions or defects or
irregularities in title, minor encumbrances, easements or reservations of, or
rights of others for, rights of way, sewers, electric lines, telegraph and
telephone lines and other similar purposes, or zoning or other restrictions as
to the use of such real property, and (ix) Liens listed on Schedule 6(a) hereto,
but not increase in the amount secured thereby, as reduced from time to time.

                (b) Merge or consolidate with any person, or make any
substantial change in the nature of its business.

                (c) Create, incur or in any manner become liable in respect of,
or suffer to exist, any Debt other than (i) Debt described in clause (d) of the
definition of Debt (ii) Debt owing to the Bank and (iii) Debt listed on Schedule
6(a) hereto.

                (d) Purchase or otherwise acquire, whether in one or a series of
transactions, all or substantially all of the business, assets, rights, revenues
or property, real, personal or mixed, of any person, or any Capital Stock of any
person.

                (e) Sell, lease, license, transfer, assign or otherwise dispose
of any material portion of its business, assets, rights or revenues or property,
real, personal or mixed, tangible or intangible, whether in one or a series of
transactions.




<PAGE>   8

                (f) Make, declare or authorize any dividend, payment or other
distribution in respect of any class of its Capital Stock or any dividend,
payment or distribution in connection with the redemption, purchase, retirement
or other acquisition, direct or indirectly, of any shares of its Capital Stock
other than dividends in shares of Capital Stock.

                (g) Enter into, become a party to or become liable in respect
of, any material contract or undertaking with any affiliate except in the
ordinary course of business and on terms not less favorable to the Company than
those which could be obtained if such contract or undertaking were in an
arms-length transaction with a person other than an affiliate.

                (h) Permit or suffer the consolidated Net Worth of the Company
and its Subsidiaries to be less than negative $40,000,000 at any time.

        7.      Representations and Warranties. The Company represents and
warrants to the Bank that:

                (a) The Company is a corporation duly organized, existing and in
good standing under the laws of the State of Delaware, and is duly qualified to
do business and is in good standing in each additional jurisdiction where such
qualification to be necessary except where failure to so qualify would not have
a Material Adverse Effect.

                (b) The execution, delivery and performance by the company of
the Loan Documents are within its powers, have been duly authorized, and are not
in contravention of law or of the terms of any agreement or undertaking to which
the Company is a party or by which it may be bound.

                (c) The Loan Documents are valid, binding and enforceable in
accordance with the terms thereof, except as such enforceability may be limited
by applicable bankruptcy, insolvency, reorganization, moratorium, or similar
laws affecting creditors' rights generally and by general principals of equity
(regardless of whether enforcement is sought in a proceeding of equity or at
law).

                (d) No consent, approval or authorization of or declaration or
filing with any governmental authority on the part of the Company is required in
connection with the execution, delivery and performance of the Loan Documents.

                (e) No litigation or governmental proceeding is pending or, to
the knowledge of the officers of the Company, threatened against the Company or
any of its Subsidiaries which could have a Material Adverse Effect.

                (f) All financial statements of the company furnished by the
Company to the Bank are complete and accurate in all material respects and
present fairly in all material respects the financial condition of the Company
as of the dates of such statements and the results of its operations for the
periods covered thereby, in accordance with Generally Accepted Accounting
Principles (subject, in the case of any statements other than year-end
statements, to year-end audit adjustments and the absence of footnotes), and
there has been no material adverse change in the condition of the Company,
financial or otherwise, since the date of the latest of such statements for the
Company.

                (g) The Company is in compliance in all material respects with
all laws, rules, regulations, orders or similar requirements of any federal,
state or local governmental authority, including without limitation those
relating to any environmental matters.

                (h) All representations and warranties contained in the Security
Documents are true and correct in all material respects.



<PAGE>   9

                (i) The Security Documents, when delivered, will grant a first
priority, enforceable and perfected lien and security interest on 100% of the
Capital Stock of Aetna Holdings and Aetna and 64% of the Capital Stock of
SOFEDIT.

        8.      Fees; Expenses; Etc. The Company shall pay the reasonable fees
and other expenses incurred by the Bank in connection with this agreement,
including without limitation the reasonable fees and expenses of Dickinson
Wright PLLC, counsel for the Bank, in connection with preparation of this
agreement and the documents required hereunder, the reasonable legal fees and
expenses in connection with any amendments or modifications hereof and the
reasonable legal fees and other expenses in connection with any event of
default, any enforcement hereof or any related agreements. Additionally, the
Company hereby indemnifies and agrees to hold harmless the Bank and its
officers, directors, employees and agents (each, an "Indemnified Person") from
and against any and all claims, damages, losses, liabilities, costs or expenses
(collectively, "Claims") of any kind or nature whatsoever (including reasonable
attorneys fees in connection with any investigative, administrative or judicial
proceeding whether or not such Indemnified Person shall be designated as a party
thereto) which the Bank or any such Indemnified Person may incur or which may be
claimed against any of them by reason of or in connection or relating to this
agreement or any of the transactions contemplated hereby, any use by the Company
of any of the Loans, under any environmental laws or due to any other activities
or transactions of the Company to the maximum extent permitted by law; provided,
that the Company shall not be liable for any indemnification to any Indemnified
Person to the extent that any Claim arises from such Indemnified Person's gross
negligence or willful misconduct.

        9.      Events of Default. The occurrence of any of the following shall
be an Event of Default hereunder unless waived in writing by the Bank:

                (a) Failure to make any payment (whether at stated maturity by
acceleration or otherwise) of principal or interest on the Note or any other
amount due under this agreement within five (5) days after any such amount
becomes due and payable; or

                (b) (i) any default in any material respect in the performance
or observance of any covenant or agreement of the Company in Section 6 hereof,
or (ii) any default in the performance or observance of any other covenant or
agreement of the Company or any of its Subsidiaries contained in any Loan
Document or other default under any of the foregoing which default shall remain
unremedied for a period of ten (10) days or more; or

                (c) any representation or warranty made by the Company herein,
in any Loan Document, document, statement or certificate furnished by or on
behalf of the Company or any of its Subsidiaries to the Bank, executed pursuant
thereto proves to be untrue in any material respect; or

                (d) the Company or any of its Subsidiaries shall fail to pay any
part of the principal of, the premium, if any, or the interest on, or any other
payment of money due under any of its Debt (other than Debt hereunder), beyond
any period of grace provided with respect thereto, which individually or
together with other such Debt as to which any such failure exists has an
aggregate outstanding principal amount in excess of $1,000,000; or if the
Company or any of its Subsidiaries fails to perform or observe any other term,
covenant or agreement contained in, or if any other event or condition occurs or
exists under, any agreement, document or instrument evidencing or securing any
such Debt having such aggregate outstanding principal amount, or under which any
such Debt was incurred, issued or created, beyond any period of grace, if any,
provided with respect thereto if the effect of such failure is to cause, or
permit the holders of such Debt (or a trustee on behalf of such holders) to
cause, any payment in respect of such Debt to become due prior to its due date;



<PAGE>   10

                (e) the Company or any of its Subsidiaries shall be dissolved or
liquidated (or any judgment, order or decree therefor shall be entered), or
shall generally not pay its debts as they become due, or shall admit in writing
its inability to pay its debts generally, or shall make a general assignment for
the benefit of creditors, or shall institute, or there shall be instituted
against the Company or any of its Subsidiaries any proceeding or case seeking to
adjudicate it a bankrupt or insolvent or seeking liquidation, winding up,
reorganization, arrangement, adjustment, protection, relief or composition of it
or its debts under any law relating to bankruptcy, insolvency or reorganization
or relief or protection of debtors or seeking the entry of an order for relief,
or the appointment of a receiver, trustee, custodian or other similar official
for it or for any substantial part of its assets, rights, revenues or property,
and, if such proceeding is instituted against the Company or any of its
Subsidiaries and is being contested by the Company or any of its Subsidiaries in
good faith by appropriate proceedings, such proceeding shall remain undismissed
or unstayed for a period of 60 days; or the Company or any of its Subsidiaries
shall take any action (corporate or other) to authorize or further any of the
actions described above in this subsection; or

                (f) the occurrence of any Material Adverse Effect; or

                (g) any change, directly or indirectly, in the ownership of the
Company other than changes by reason of the transfer of Capital Stock of the
Company (i) pursuant to applicable laws of descent and distribution or among
such transferee's spouse and descendants (whether natural or adopted) and any
trust solely for the benefit of the transferee and/or other permitted
transferees, (ii) to any person, directly or indirectly controlling, controlled
by or under common control with such transferee and any partner or member or
similar interest of a transferee which is partnership or limited liability
company or similar entity, respectively, and (iii) to stockholders by reason of
a dividend of shares of Capital Stock.

                Upon the occurrence and during the continuance of any Event of
Default, the Bank may terminate the Commitment or declare the Note and all other
amounts due hereunder or pursuant to the Note to be immediately due and payable,
or both, provided that in the case of any Event of Default under clause (e)
above the Commitment shall automatically terminate and all such amounts shall
automatically become due and payable, without notice. Additionally, upon any
Event of Default the Bank may exercise all of its rights and remedies under the
Loan Documents, under any other agreement or otherwise provided by law or
available to the Bank. In addition to the foregoing, upon the occurrence and
during the continuance of any Event of Default, the Bank may at any time and
from time to time, without notice to the Company (any requirement for such
notice being expressly waived by the Company) set off and apply against any and
all of the obligations of the Company now or hereafter existing under or
pursuant to this agreement, any and all deposits (general or special, time or
demand, provisional or final) at any time held and other Debt at any time owing
by the Bank to or for the credit or the account of the Company and any property
of the Company from time to time in possession of the Bank, irrespective of
whether or not the Bank shall have made any demand hereunder and although such
obligations may be contingent and unmatured. The Company hereby grants to the
Bank a lien on and security interest in all such deposits, Debt and property as
collateral security for the payment and performance of the obligations of the
Company under this agreement. The rights of the Bank under the foregoing
sentence are in addition to other rights and remedies (including, without
limitation, other rights of setoff) which the Bank may have.


        10.     Notices. All notices, demands, request and consents hereunder
shall be in writing and shall be effective when received, except that any notice
or demand which by any provision of this agreement is required or provided to be
given or served to or upon the Company shall be deemed to have been given or
served for all purposes by being sent as registered mail, postage prepaid,
addressed as follows: MS Acquisition Corp., 24331 Sherwood, Centerline, MI
48015, Attention: Harold Brown, Telephone No. (810) 759 2200, Telecopy No. (810)
759 0508, MS Acquisition Corp. 1, Rue Thomas



<PAGE>   11


Edison, Quarteir des Chenes B.P. 605, 78056 St. Quentin en Yvelines Cedex,
France Telephone: 011-331-39-41-2000, Telecopy No. 011-331-30-48-5391,
Attention Jean-Claude Garolla or, if any other address shall at any time be
designated by the Company in writing to the Bank, to such other address.

        11. Miscellaneous. The Loan Documents embody the entire agreement and
understanding between the Company and the Bank and supersedes all prior
agreements and understandings relating to the subject matter hereof. No
amendment, modification or waiver of any provision of this agreement nor any
consent to a departure therefrom shall be effective unless the same shall be in
writing and signed by the Bank and the Company. No failure of the Bank or of the
holder of the Note in exercising any right, power or privilege hereunder shall
affect such right, power or privilege, nor shall any single or partial exercise
thereof preclude any further exercise thereof or the exercise of any other
right, power or privilege. The rights and remedies of the Bank and those of the
holder of the Note under this agreement are cumulative and not exclusive of any
rights or remedies which either of them may otherwise have. All payments to be
made by the Company hereunder shall be made in immediately available funds to
the Bank at its main banking office in Detroit, Michigan not later than 1:00
p.m. Detroit time on the date on which such payment shall become due, and all
payments received after 1:00 p.m. shall be deemed received on the following
Business Day. All payments due hereunder which are not due on a Business Day
shall be due on the next succeeding Business Day and interest shall continue to
accrue at the applicable rate. All financial terms used but not defined herein
shall be interpreted in accordance with generally accepted accounting
principles.

        12. Waiver of Jury Trial. The Bank and the Company, after consulting or
having had the opportunity to consult with counsel, knowingly, voluntarily and
intentionally waive any right either of them may have to a trial by jury in any
litigation based upon or arising out of this agreement or any related instrument
or agreement or any of the transactions contemplated by this agreement or any
course of conduct, dealing, statements (whether oral or written) or actions of
either of them. Neither the Bank nor the Company shall seek to consolidate, by
counterclaim or otherwise, any such action in which a jury trial has been waived
with any other action in which a jury trial cannot be or has not been waived.
These provisions shall not be deemed to have been modified in any respect or
relinquished by either the Bank or the Company except by a written instrument
executed by both of them.

        13. Governing Law. This agreement shall be governed by and construed in
accordance with the laws of the State of Michigan applicable to contracts made
and to be performed entirely within such State and without giving effect to
choice of law principles of such State.

        14. Binding Effect. All representations, warranties, covenants and
agreements herein contained shall be binding upon and inure to the benefit of
the respective successors and assigns of the parties hereto whether or not so
expressed.

        Should the foregoing be agreeable to you, as it is to us, please
indicate your agreement and acceptance by executing and returning the enclosed
copy of this letter, whereupon this agreement shall be effective as of the date
of this letter.


                                                Very truly yours,

                                                NBD BANK


                                                By:  Thomas A. Gamm
                                                     ------------------

                                                Its:   Vice President
                                                       ---------------





<PAGE>   12
Agreed and accepted:

MS ACQUISITION CORP.


By: Felix Domenech

     Its:   Executive Vice President-Finance

By: Jean-Claude Garolla

     Its:   Vice President & Chief Financial Officer

<PAGE>   13




                                   EXHIBIT A

                                      NOTE

$10,000,000                                                      March 31, 1999
                                                               Detroit, Michigan

        ON the Termination Date, for value received, MS ACQUISITION CORP., a
Delaware corporation (the "Company"), hereby unconditionally promises to pay to
the order of NBD BANK, a Michigan banking corporation (the "Bank"), at the
principal office of the Bank, in lawful money of the United States of America
and in immediately available funds, the principal sum of Ten Million Dollars
($10,000,000), or such lesser amount as is recorded on the schedule attached
hereto, or in the books and records of the Bank; and, to pay interest on the
unpaid principal balance hereof from time to time outstanding, in like money and
funds, at the rates and at the time set forth in the Letter Agreement referred
to below.

        This Note evidences one or more loans made under a letter agreement of
even date herewith (as amended or modified from time to time, the "Letter
Agreement"), by and between the Company and the Bank, to which reference is
hereby made for a statement of the circumstances under which this Note shall be
immediately due and payable without notice or demand, the collateral security
for this Note and other terms relating hereto. Terms used but not defined herein
shall have the respective meanings ascribed thereto in the Letter Agreement.

        The Bank is hereby authorized by the Company to record on the schedule
attached to this Note, or on its books and records, the date, amount and type of
each loan, the applicable interest rate (including any changes therein), the
amount of each payment of principal thereon and the other information provided
for on such schedule, which schedule or such books and records, as the case may
be, shall constitute prima facie evidence of the information so recorded,
provided, however, that any failure by the Bank to record any such information
shall not relieve the Company of its obligation to repay the outstanding
principal amount of such loans, all accrued interest thereon and any amount
payable with respect thereto in accordance with the terms of this Note and the
Letter Agreement.

        The Company and each endorser or guarantor hereof waives demand,
presentment, protest, diligence, notice of dishonor and any other formality in
connection with this Note. The Company further agrees to pay, in addition to the
principal, interest and other sums due and payable hereon, all costs of
collecting this Note, as set forth in the Letter Agreement.

        This Note is made under, and shall be governed by and construed in
accordance with, the laws of the State of Michigan applicable to contracts made
and to be performed entirely within such State and without giving effect to
choice of law principles of such State.

                                                 MS ACQUISITION CORP.


                                                 By:
                                                    ----------------------------

                                                     Its:
                                                          ----------------------


<PAGE>   14


                             Schedule to Note, dated
           March 31, 1999, issued by MS Acquisition Corp. to NBD Bank

<TABLE>
<CAPTION>


Transaction          Principal           Interest          Principal        Principal Balance       Notation
  Date             Amount of Loan          Rate           Amount Paid          Outstanding           Made by
  ----             --------------          ----           -----------          -----------           -------
<S>               <C>                      <C>             <C>                 <C>                   <C>
</TABLE>