I have a swreg.org account and i want a simple ipn to help me send serial keys to customers after they make a payment. 1. I will add a bunch of serial keys in the software script on my site 2.User enters their email address on my site before going to the swreg site for payment. 3.after successful payment, the ipn notifies my site and one serial key is sent to the user's email address.Each user gets one serial key and once a serial key is sent to a user it is removed from my site so we do not make a mistake and send that same key to another customer. Thanks