But, the package that I get sticks r600 in /usr/lib/dri. So you can put a link to /usr/lib/dri in /usr/lib/xorg/modules/dri.
But then I still get dri disabled. I imagine the software is just not ready yet or I'm goofing it up. This for a HD3200. Your results may differ.
Simple answer: the software is not ready yet. You're talking of OpenGL support, it's completely irrelated with EXA+Xv support and doesn't work yet.
(also the path it put the driver in is correct on a 32bit system)