I've installed the online gift card contribution ( http://addons.oscommerce.com/info/5527 ) in my 2.2 RC2 shop, and it works perfectly except for when a customer pays by PayPal.
When paying by PayPal, the gift voucher processes correctly from the customer's perspective, but it retains all of its value. For example, when a gift card has $12 left, and the customer makes a total purchase of $18, they pay $6. If paying by credit card, the gift card's value is deducted by $12, but when paying by PayPal, the gift card keep all of its value.
I'm at a loss as to where to fix the issue exactly, but I suspect I need to find a way to pass information through the PayPal payment module which is then passed back to the checkout_success.php page, which I could then add code to remove the value from the gift voucher.
But I don't know how to do this. If this is as simple as I'd think for someone familiar with the IPN, I'd be willing to pay to get this done. Or... could you point me in the right direction?