If you create one Invoice for the sale, QBs only let's you set one payment due date.
What I would have done is create an Estimate for the full amount to give the customer. Then I would set up a Invoice for the first Month's payment and set it up as a Memorized transaction that automatically generates each month for the remaining 59 months. That way, each payment has it's own due date and will show up correctly in the A/R aging reporting. It's up to you whether you send out these monthly invoices or not to the customer.
