Facebook ultimate i need to add the user email in the /regrister/ URL

My setup currently has registration only by invite and i am using the plugin Secure Invites for that.

The process is simple, once the user has been invited it receives a link to register via email. This link has domain.com/register/?email=my@email.com

Now with the Ultimate facebook i get the screen telling me that i need to be invited since Ultimate facebook does not add the email to the /register/ url after user has commited the form.

Is there anyway to add the email into this URL ?

Thank you