Connecting a sign-up page to payment gateway page

I have a 开发者_JAVA百科signup page, which allows user to provide his information like (name, address, dob, sex, ph # etc etc)

Once the user gives out this info, it gets stored into a MYSQL DB table and the page gets forwarded onto a second page where user can select from the available subscription packages and add them into paypal payment gateway..

This all works now, except that right now there is no way of knowing on whose behalf payment was made except the billing address they provided on payment gateway page which could be different from what they gave at sign up page..

How can i link these pages?

Thanks for help

---

Do you store the billing address as well?

One design you can do is; after signup you store a unique id into a SESSION variable. The unique id can be the id where you store the data from the signup page. Once the user goes to the subscription page and enter their billing address you can either store the billing address in the signup table based on the unique id in the SESSION variable. In that way it will link both the signup record to the billing address