I would like to use my own form for creating the User Registration fields. More specifically, I'd like to use Gravity Forms to create the registration form, then pass that info into s2Member. I'm assuming I can't just directly submit my info into s2Member, but rather I can pass the data from the submitted Gravity Form into the s2Member registration page. I've seen Jason mention having your own form submit to /wp-login.php?action=register, which I can do in Gravity Forms, but it doesn't seem to actually pass any data through.
How do I set it up to pass the data to the s2Member registration?