Here is how this works at version 9 (nothing is created manually):
1) Find the Delivery Order representing when you originally sent the Customer the items.
2) Click REVERSE.
3) Change the default quantity being returned to match what is actually being returned.
4) Click RETURN to create a Receipt.
5) Click VALIDATE to process the Receipt.
1) Find the Invoice representing when you originally Invoiced the Customer.
2) Click REFUND INVOICE.
3a) If the Customer has already paid you, select "Create a draft refund"
3b) If the Customer has not already paid you, select "Modify: create refund, reconcile and create a new draft invoice"
4) Enter a reason and the refund date and click CREATE REFUND.
5) Open and edit the Invoice to reflect what you are refunding, adjusting for restocking fees, shipping, etc.
6) Click VALIDATE to open the Invoice.
Use Payment Matching (from the Accounting Dashboard) if you need to apply the refund credit to another order, otherwise you can pay it and generate a check or other payment back to your Customer.