PO Confirmation

We are using 9.2 and our purchasing group is looking for a way to capture if a purchase order has been confirmed by the vendor or not.  Do other clients do this, and if so, how?

We create POs and then send to the vendor via email.  Most of our vendors are not using EDI.   They then confirm back to us via email or a signed copy of the PO so that we know they can fulfill it and at the qty and cost.  We attach those to the PO for our records, but would like to be able to inquire on PO's that have been confirmed or not.  This would be done somehow at the header record so that users could inquire or report on easily.