Allow entry of PO number on Web Invoice or allow editing after posting/payment of a Web Invoice in Accounts Payable - this is useful for when WebPurchasing is used for tracking POs and Invoices are entered to indicate the PO has been processed. This would be useful in the event that an end user forgets to add in the PO number before posting or payment. This is not a problem with Invoices entered directly through Accounts Payable.