I've written a website to display and sell cards. It looks like I can use PP to do the billing, but as I look around the website all I see is lots of information about the features. Nothing about how to do it. Basically what I need to do is to be able to send them to PP with an amount, my account information, and their invoice number. Then get a response from PP that the bill has been paid. Seems like it should be simple, but I'm totally lost....
