Credit Memo generation using Autoinvoice master program

  Dear Friends

      We use the Autoinvoice Master program with Parameters for Invoice source as  Credit Memo from OM. we do not wish to give the Sales order nos in the   parameters    for Transfer of Credit Memos from OM to AR. We wish to get different CM for different RMA for the same Customer. How can I achieve the same.  At present the system raises one Credit Memo for One Customer even if there are different Return Sales Order.

Regards

Ramanathan