Wildcard SSL Certificate

Ok,
I’ve got a question that I hope somebody can help me with. I’m running WPMU 2.8.2. I have multiple customers within my platform that would like to use the Paypal Pro plus other “On Site” payment gateways.

The problem is that on a WPMU installation if you want to install a SSL Certificate you need a Private IP. With a private IP you are only allowed 1 SSL Certificate ( I know about the Multiple Domain (UCC) Certificate, but this still limits the number of customers to any particular WPMU install and is a little spendy ), I have customers that use their own personalized domain such as https://www.theirdomain.com and I also have customers that use one of our subdomains such as https://www.theirdomain.sitesires.com.

If I install the Wildcard SSL Certificate this will enable me to secure all my subdomain customers.

If I install a SSL Certificate for one of my customers that own a personalized domain then I cannot install the Wildcard so all of my subdomains and the rest of my personalized domain customers would be SOL.

What I want to do is this. Since even the personalized domains such as https://computersforseniorsandkidsofallages.com is REALLY located at https://computersforseniorsandkidsofallages.SITESIRES.com, is there a way to:

1. Install Wildcard for all subdomains so that only checkout page is secured.
2. Make it so that if someone clicks on the “Proceed to Checkout” button for

https://computersforseniorsandkidsofallages.com/shop/checkout

(which is unsecured) they are forced to go to

https://computersforseniorsandkidsofallages.SITESIRES.com/shop/checkout

(which is secured)

Any help would be greatly appreciated. I know that there HAS GOT TO BE A WAY TO DO THIS, I just don’t know exactly how to achieve what I want to do in this case.

Thanks a bunch!

Courtney Bostdorff