Fixed Asset Flag in Payables

Is there a way to set the fixed asset flag on the payables invoice lines after it has been invoices/paid, in order for the invoice to be picked up via the create mass additions program? Our Fixed Assets folks don't want to set the flag at the time the invoice is created and validated.  This forces fixed assets to go and find invoices that should have been flagged and enter them through the Asset Workbench. It would be easier for us to set the flag in payables and run the Mass Create program. We can set the flag, but the