Dynamics SL support question

I am attempting to configure a Counter Sale order type in Dynamics SL OM version 2011 FP1.  The key aspects I am attempting to configure are as follows:

1. For Cash Sale customers:

   1. The user should be able to enter a shipper

   2. Finish the shipper

   3. But if a payment has not been entered block the printing of an invoice and put the shipper on hold. (hold or credit hold either way)

   4. If a payment has been entered, it should automatically print the invoice and close the shipper as normal.

2. For Credit customers…  the system should allow invoicing of course regardless.

I attempted to configure the cash sale customer with terms/credit option of COD or with a credit limit of 0.01 however even when the customer exceeds the credit limit the invoice is still printed.  Is there any way to stop the invoice for cash sale customers from printing if a full payment has not been entered?