Bleary

Hi all, I've just started using this brilliant software and am very happy with it, the only difficulty I'm having is with getting a deposit entry on the invoice. I'd like it to be between the "Subtotal" and "Total Amount" box at th bottom of the invoice. If it can't be placed there then anywhere would be fine. At the moment I'm having to enter deposits by putting the word DEPOSIT in the "Description" field then putting a negative entry in the "Unit price" field. Can it be done?