Sales Return functionality

In the SAP client, you are allow to create a return request document based on an A/R invoice document. However, with Produmex WMS via the scanner, you are only allowed to create a Return document based on a return request document with no base document. I have a lot of clients complaining about this limitation. Produmex WMS should be able to create an A/R credit memo document instead once the return request document has a base entry