I'm writing a plugin for 1.57c and among other things I need to observe the amount of a refund, preferably independently of the payment module performing the refund. I can see in admin/orders.php I could place a notifier into the "doRefund" action but it looks as though orders.php doesn't get visibility of the actual refund amount. The form containing the amount is generated and processed by the payment module itself.
Is there a generic way I can observe a refund taking place and see the refund amount or do I have to hook into each payment module individually (effectively ruling out making this a general plugin)?