Ability to add an invoice date in addition to the already supplied shipment date. Also the ability to add notes no an invoice.
Hi Elliott, there is a patch for invoices you might want to look at before getting started on this - bug 5339. It will add a new table for invoices and probably makes adding your 2 fields easier too if there is not already something like that.
*** This bug has been marked as a duplicate of bug 6850 ***