ngoodfellow on "SSL and Contact Form 7 Wordpress Multi User Site"

I am trying to get contact form 7 to work with my wordpress multi user site. here is my current structure:

primairydomain.com - has SSL
secondairy.primairydomain.com - does NOT have ssl

I would like to redirect all contact form 7 submits from secondairy.primairydomain.com to https://primairydomain.com

this is the code I have so far, just not sure how to finish it to make it work. I was told this hook in functions.php will allow me to modify the contact form 7 submit location

add_filter('wpcf7_form_action_url', 'wpcf7_custom_form_action_url');
function wpcf7_custom_form_action_url()
{
    return '????????';
}

what should the return be to make the contact forms work?

please help!

http://wordpress.org/plugins/contact-form-7/