apache mod_rewite rule help

[xkaliburx]

There are alot of examples, etc. but having a problem getting this to work. We have a login page (box) that can appear on any page by clicking the login button opening a simple login page. For PCI req's, that must be behind an https page, so I wish to simply look on the URL, if it sees the login request, to redirect, but still keep the page there on, so if there were at www.mydomain.com/page1.cfm redirect them to https://www.mydomain.com/page1.cfm?showLogin=true

I have the following rule;

RewriteRule showLogin=true https://%{DOCUMENT_ROOT}%?showLogin=true

Now I don't see any errors, but not sure if they would spit out, but when I goto www.mydomain.com, hit any page, then hit the login, I simply stay on that page; http://www.mydomain.com/xyz.cfm?showLogin=true (and the login box appears) but no redirect.

Thanks.