Accounts Receivable Payment Terms Combining Discount and Installments


I am trying to setup the payment term 1% 60 Days, 4 Pay Sept 15. The way I wish for this to work is as follows:

*** A $1000 sales order has an invoice date of 1-JUL-2014

*** If the customer pays the entire invoice within 60 days, they can take a 1% discount and pay $990.00

*** If the customer chooses not to pay the entire invoice within 60 days, then they can pay in installments
$250 will be due on 15-Sep-2014
$250 will be due on 15-Oct-2014
$250 will be due on 15-Nov-2014
$250 will be due on 15-Dec-2014

I know how to setup the installments, but I am having a difficult time incorporating the 1% for the entire invoice. Any assistance would be greatly appreciated.