Yay GUI apps that don't work!
There is no "magic switch" that turns on or off 3D acceleration with these drivers. Not having a Load "glx" in your config file is a good way to disable it, but you very likely have that line in there.
The best test is not to run something that was written to only understand the DRI drivers -- RH's (I'm assuming RH, is that right?) display settings dialog -- but something that actually looks at whether direct rendering is enabled -- glxinfo.
Run glxinfo | grep -i direct
, and that should print out either "direct rendering: yes" or "direct rendering: no". If it says yes, then it is very likely that 3D acceleration is enabled. If it says no, then 3D won't work, and you'd have to look at your X log (or at the rest of the messages that glxinfo gives) to find out why. But I'm betting it'll say yes.
The other test you can do is to run glxgears
. Every 5 seconds, glxgears prints a framerate to the console that you start it from. If this framerate is low ("low" meaning <1000fps given a decent video card), then you probably don't have 3D acceleration enabled -- check the X log and the console you used to start glxgears, for info on why.
The third test is to run tuxracer. If it runs at more than 1 frame every 3 seconds, you have a working OpenGL+glx setup.