My client requirement is that if in customer mast tax claissification is maintained as cst 2% and if CST number is not mainted for him in master data
while creating sales order system should give error that CST number is not maintained for this customer.
in case if it is maintained there should not be any error .
System should prompt error as soon as he enters the customer number in sales order.
I would like to know whether it can be done through enhancement or should write any routine for the condition type zcst.
Please guide me wheter to write the logic so that it triggers as soon as the customer number is entered in sales order.
pl do the needful