Selling products and using U-Rewards card/GC (no loyalty card balance effect) to redeem against the sale where product value is Less than U-Rewards card/GC
Add in the customer to the sale
Add in the product lines to sale
Add in the product GC
Make the GC product have a quantity of -1
Make the GC product price inc be value of the difference between the GC / U-Rewards card and product sales value inc tax (i.e if product lines totalled $20 and gc/urewards card is $50, then line price for gc/urewards product would be $30.00)
Complete the sale tendering the sale to GC with the value being the total value of the GC / U-Rewards card.
Tell your customer to keep their invoice as proof that they still have an outstanding balance of the difference on their gift card GC / U-Rewards card.