ewok, I found the answer. I went to the page with the CAT_Cart module on it. For me that was "Cart" in the "My Account" part of the menu. Open the view options for the cat_cart. Scroll down to the credit card options. Check the first option. It looks like this:

_______________________________________ Credit Card Options

Redirect Credit Card Data Form to SSL (https)? (No SSL connection for the CC form is used on localhost) _______________________________________ After doing that, I tested purchasing something. When I go to the page requesting the cc number, the browser bumped the session to an https:// session. When I cancelled the order, it bumped me out of https and back to http. That is just what I needed. (I'm assuming you know you need to arrange for an ssl certificate from someone like thawt or Verisign and have it installed on your host server first.)

You can use any DNN SSL manager for that e.g. the module from Tom Thorp:

http://www.snowcovered.com/Snowcovered2/Default.aspx?tabid=242&PackageID=4285&search=&pagenumber=0&sortby=&tagid=77&tagid=372