Pondering Mod in Invoicing

I wonder if anyone could give me some pointers on a mod I believe I need to do. Several of my client’s vendors use factors (essentially banks/collection agencies that handle their invoicing). These factors are set up in Navision as vendors. The problem is that at the time a PO is placed with a vendor, they do not know who the factor (the pay-to vendor) will eventually be. My client does not know this until they receive the vendor invoice. Invoices at my client are built from the Purchase Invoice form, using the Get Receipts function. The invoice is generated and the receipt lines added no problem, but then the Pay-to vendor must be changed to reflect the factor. This causes a problem because the system does not allow the pay-to vendor to be changed if receipts have been pulled in (the receipts all have the original vendor on them), or if the pay-to vendor is changed first, no receipts are visible (since they are filtered on the current pay-to vendor). The trigger in question is in table 38 Purchase Header, Pay-to Vendor No. OnValidate(); line 21 { PurchLine.TESTFIELD(“Receipt No.”,’’); } is where the Break On Error occurs. I would like to put a trap here that displays a messagebox asking if the user wants to change the pay-to vendor on the receipt line. If the response is ‘yes’, I would execute the change and hopefully continue. Has anyone else done something similar? Any gotchas or dangers to look out for here? Thanks… Chandler