Hi,
Try blocking the user from entering payment data using a transaction notification. Here is a script I used to force a user to select payment means before adding a down payment. You can change the table names and the condition.
IF @transaction_type IN ('A','U') AND @object_type = '203'and @error = 0
BEGIN
IF NOT EXISTS (select T0.docnum from ODPI T3 inner join ODPI T0 on T0.DocEntry=T3.DocEntry
left join RCT2 T4 on T4.[DocEntry] = T3.[DocNum] INNER JOIN ORCT T5 ON T4.DocNum = T5.DocEntry
WHERE T0.DOCENTRY = @list_of_cols_val_tab_del)
BEGIN
SELECT @Error = 35, @error_message = 'Please enter the payment means'
END
END
With regards
Job