FB60 - Payment method

Hi all,

I have a problem in the transaction FB60: when I create a FI document with a single amount or when I split the amount, I need to implement a check on the payment method.

This check must control the payment method is not initial in the screen number 20 (Payment) or 90 (Split Amount - in this case for all the lines).

I tried by FI validation (transaction OB28) but I haven't the value on-line (screen number 20: INVFO-ZLSCH; screen number 90: ACSPLT-ZLSCH) in the program ZGGBR010, so I can't do the check.

I haven't found any User-Exit, do you know a method for implement this check (without modify the standard program SAP)?

Thanks for your help.

Regards.