We are giving a partial refund to a customer whose invoice and payment by credit card is in a previous month.  We have created a Credit memo (with a Sales Order for a sales discount) and now are wondering how do we pay it with a customer's credit card?  We can't do a payment because the only two choices are NSF or reversal of a check.  Or do we use this and just make up a check number that does not match one already in the system?  The other method, Enter Customer refund, creates a AP voucher which we can't pay with the customer's credit card.
 
Any suggestions??