Sorry, I don't mean to spam the board or blather on about stuff I don't know much about.
I'm just trying to help, because there are a bunch of people that need this fixed.
Anyway, here's some information on Paypal about data transfer and IPN, including the code you need.
I have not installed it yet.
You will recieve this if you enable Payment Data Transfer, via Paypal.
I have not looked at the OSC contributions for any of this.