AP30.2 and Missing PO from original distribution

We often have to redistribute an expense that has already been paid. So we use AP3.02 to complete the redistribution. However, we are not able to include the PO associated with that purchase, and therefore the PO is no longer connected to the expense in it's new distribution. We're told this is by design, and the only way to change this would be to redo the entire AP process. Is there another way?