Well, what I did way back when I didn't have ModernBill and was only using PayPal...was I had an order form that I made on the website...when submitted, it sent all the variables via email and I had the EXIT page as the PayPal page. This way, you had all of the client information even if they didn't make the payment. Often, people were unable to figure out the PayPal system and couldn't complete the payment. After a few emails of coaching, they eventually got it. Without their information though, I would not have been able to do that.
You're welcome...business is doing really well these days actually. Oddly enough, the amount of time I spend on WHT hasn't warranted me one customer here (at least none that I know of), but what can you do? We're conquering our local market
1) User goes to regular HTML form on website
2) User clicks on SUBMIT
3) Form access a PHP script that emails the values of the fields
4) After email is sent, user is re-directed to PayPal payment page