Preventing zero $ invoice to be sent out

Hello, With the output parameter determination, we do not have access to create requirement like we did on the hold output procedure. I have look to add criteria in the table decision in order to preven sending 0 $ invoice to customer. In a situation where we are using the on account billing, we will send the invoice for the paiement required (on account) but we do not want to send invoices for the time and expense that consumes this amount. Does anybody know how to prevent sending 0 $ invoices ? pascale