We use Accounting periods and we need an AR report that will help us reconcile my GL AR account.  The report should include only open invoices posted to Accounting Periods up to and including the period I wish to reconcile, then add back payments recieved for invoices that were posted to Accounting Periods AFTER the period I am reconciling (prepayments).  The end result would agree to the GL balance.

Does one such report exist, or....does anyone know how to customize an existing report (say the existing AR Aging Detail Report) to achieve this?  The problem is that the standard reports key on the transaction date of the invoice rather than the accounting period (I can run a search to find prepayments).  I've talked to customer support but to no avial.