Job Planning and Accrued Cost

Developer101

In NAV 2009 and in Job Module I have a job for which I have created Job planning line as sales invoice of type G/L account. Unit Price is 80 and Unit Cost is 15 (Line type is 'Both Schedule and Contract')

15 is recorded as Accrued Cost. Now how can I link the purchase invoice that would come in later to clear the accrued cost? Any one has an idea, please share.

Thanks,