For some reason your second post didn't show up the first time I responded.
Actually, I couldn't find my question in the forum when I first posted it. Not until some 30 minutes or so. Automattic folks do some serious-level caching, lol!
This functionality is built-in to WordPress. Please read the FAQ. Let me know if you need anything else.
Actually, I don't want to force HTTPS on WP-ADMIN, as some plugins (like wp-touch pro) aren't great with SSL (at least for me they're broken).
All I want is to force HTTP on the rest, and let WP-ADMIN be accessible via both HTTP and HTTPS.
get me now?
And Your plugin is working great now. It's redirecting all pages from HTTPS to HTTP, with the exception of WP-ADMIN without any additional config, which is great. (1) That is how it's supposed to work, right? (2) is it 301 redirecting here right, are you sure? If not is there a way to enable it?
Lastly you'll continue to support your plugin for the foreseeable future, I hope? (Please, I don't want to go searching for another plugin when there's a new wordpress version and your plugin is broken.)
This is the screenshot of my config. which I feel is enough for what I need: http://img1.uploadscreenshot.com/images/orig/8/23913514217-orig.jpg