How to settle debit claim with RMA

We have a business need to create a debit claim, and settle it with an RMA that will eventually get booked in Order Mgmt. and create an Invoice transaction in AR to bill the customer.  Within Trade Management, the only settlement methods available for a Debit Claim are:

                   Debit Memo

                   Previous Open Debit Memo

We have attempted to add the settlement method of Return Material Authorization within the Claim Source Setup menu, but it's not available.

If you know how to add this settlement method please respond.