I have a need to redirect or extend UserUpgradeProcessor/PayPal.php to a different processor. I know I discussed this with someone about a year ago and the conclusion was it couldn't be done. Not that I don't believe them, but perhaps someone has a way it can be done. The situation is I'm using a different payment_callback.php file for new transactions, but there are existing recurring transactions being sent to the standard payment_callback.php file. I need those recurring transactions to process through my new UserUpgradeProcessor/PayPal.php.