How to get AutoInvoice to properly derive GL date on imported Invoices and credit memos

The company I work for recently upgraded from 11i to release 12.  The issue they are presently having they claim they did NOT have in release 11i.  That being said here is the problem.  A little backround - the company creates orders that remain open for up to 18 months. When ever a customer wants to order or return product - the same order header is used and a line is created for ordering the product or returning the product.    THese lines are then passed to the interface tables in receivables for import.  The only date that is passed is the original sales order date from