We have a customer return some items that were origonally
charged on his credit card.
 
We have credited the credit card charge, printed and posted
a credit memo.
 
What do I do now to enter the credit card refund into DBA
so that I can offset the credit memo that is now on account?
 
When we do CC orders, we enter the Credit card charge
as a customer deposit with the Authorization # as the
check number.  This way, we can show the credit card payment
as a deposit on the invoice and the invoice total due is $0.
 

Since there is an open credit on the customer account, just use AR-M and process a refund through the credit card bank account (or your regular bank account if you don't have a separate one set up for CC) to pay them back.