Ok, it's been forever since I've done anything with this, but I've updated to the latest version of AntTweakBar and added support for StingVariables. The latest version has much more consistant results as far as the custom icons under Windows, which is nice and they added support for DX10, which I have left out for now since Ogre doesn't have a DX10 RenderSystem. I updated the Demo to show a StringVariable. The next thing I am going to work on is the callback system and buttons.
You can check this update out at:
svn checkout http://twogregui.googlecode.com/svn/trunk/
If you use the Ogre SDK then you should be all set. TwOgre should build right out of the box for you.
If you Build Ogre from Source then you'll need to add the OGRE_SRC environment variable to point to your ogrenew folder. Then TwOgre should build with no problems.