How to re-route the register button to Jomsocial

Hello my friend I have tried everything to secure my registration against spams .Unfortunately I can't seem to be able to insert a captcha in the nice drop down effect you guys put in the registration button. So my question is: in order to stop spam , is there a way I can redirect the registration button to Jomsocial where there is a captcha?

P.S If someone by any chance has figured out a way to insert captcha in the template default registration, please let me know and your help will be greatly appreciated.
Thank You