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                                                                  EXHIBIT 10.1.6


                                    ADDENDUM
                                       TO
                            STOCK PURCHASE AGREEMENT


         The following provisions are hereby incorporated into, and are hereby
made a part of, that certain Stock Purchase Agreement (the "Purchase Agreement")
by and between BPO-US, Inc. (the "Corporation") and
_____________________________ ("Optionee") evidencing the shares of Common Stock
purchased on this date by Optionee pursuant to the option granted to him or her
under the Corporation's 1999 Stock Option/Stock Issuance Plan, and such
provisions shall be effective immediately. All capitalized terms in this
Addendum, to the extent not otherwise defined herein, shall have the meanings
assigned to such terms in the Purchase Agreement.

                        INVOLUNTARY TERMINATION FOLLOWING
                              CORPORATE TRANSACTION

         1. To the extent the Repurchase Right is assigned to the successor
corporation (or parent thereof) in connection with a Corporate Transaction, no
accelerated vesting of the Purchased Shares shall occur upon such Corporate
Transaction, and the Repurchase Right shall continue to remain in full force and
effect in accordance with the provisions of the Purchase Agreement. Optionee
shall, over his or her period of Service following the Corporate Transaction,
continue to vest in the Purchased Shares in one or more installments in
accordance with the provisions of the Purchase Agreement. However, upon an
Involuntary Termination of Optionee's Service within eighteen (18) months
following the Corporate Transaction, the Repurchase Right shall terminate
automatically, and all the Purchased Shares shall immediately vest in full at
that time.

         2. For purposes of this Addendum, the following definitions shall be in
effect:

               An INVOLUNTARY TERMINATION shall mean the termination of
Optionee's Service by reason of:

                  (i) Optionee's involuntary dismissal or discharge by the
         Corporation for reasons other than for Misconduct, or

                  (ii) Optionee's voluntary resignation following (A) a change
         in his or her position with the Corporation (or Parent or Subsidiary
         employing Optionee) which materially reduces his or her duties and
         responsibilities or the level of management to which he or she reports,
         (B) a reduction in Optionee's level of compensation (including base
         salary, fringe benefits and target bonuses under any
         corporate-performance based incentive programs) by more than fifteen
         percent (15%) or (C) a relocation of Optionee's place of employment by
         more than fifty (50) miles, provided and only if such change, reduction
         or relocation is effected by the Corporation without Optionee's
         consent.

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         MISCONDUCT shall mean the termination of Optionee's Service by reason
of Optionee's commission of any act of fraud, embezzlement or dishonesty, any
unauthorized use or disclosure by Optionee of confidential information or trade
secrets of the Corporation (or any Parent or Subsidiary), or any other
intentional misconduct by Optionee adversely affecting the business or affairs
of the Corporation (or any Parent or Subsidiary) in a material manner. The
foregoing definition shall not be deemed to be inclusive of all the acts or
omissions which the Corporation (or any Parent or Subsidiary) may consider as
grounds for the dismissal or discharge of Optionee or any other individual in
the Service of the Corporation (or any Parent or Subsidiary).

         IN WITNESS WHEREOF, BPO-US, Inc. has caused this Addendum to be
executed by its duly-authorized officer as of the Effective Date specified
below.


                                 BPO-US, INC.


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

                                 Title:
                                         ---------------------------------------




EFFECTIVE DATE:  _____________, 199___


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