ssl cross domain HELP MEEE ;)

I have many domain names on one website that are all relative to that site. I have purchased an ssl because I am not accepting payment online. I have one ssl site that has one domain name and it is https://secure.mydomain.com What I am doing is as soon as the shopper tries to go to their cart, "from one of the none secure sites" I do a response.redirect("https://secure.mydomain.com"). When i do this there is one little browser out there that does not like this, and that browser is IE. I get a data from previous site is not secure do you want to proceed.? And it does this for every new page that is opened up. I have read cross domain articals and it looks like they are for sub domains and not totally different domains. How can i go from http://greencolors.com to https://secure.colors.com ? and not get the warnings? ...