Generate serial numbers on purchase order confirmation


I am trying to setup AX 2012 R3 to allow me to generate serial numbers for items when I confirm the purchase order.  I cannot seem to get it to create these numbers before the receipt of the PO.  I need the serial numbers to be generated when the purchase order is confirmed so that the receiving dept. can get material tags created with those numbers before the shipment arrives.  Is it possible to set this up or would it be a customization?