Deposit Application

Hello all, yet another problem with navision 3.60,
When i'm doing deposits, and applying them on invoices for customers, giving them a discount is causing problems, since discounts are not being posted to the customer ledger unless the invoice gets completely closed, i believe this problem was solved in navision 4.0 but im not sure, has anyone ever come across this issue? and is there a way to fix this without changing the code , i.e. something in the setup maybe

thanks.
Saro