Adding Popup User Registration Form to a Different Button

URL http://www.alumniclubny.com

Versions
WordPress 3.5.1
Membership 3.4.3.1
PHP Version 5.2.17
MySQL 5.5.30-log

I have already tried disabling all of my other plugins.

I would like to use your popup user registration form, but I wanted to do it from a different part of my site (using one of my own buttons) – how would I go about doing this?