Forcing Radeon Gallium3d in !Ubuntu Natty

Gallium will be enabled by default in the final version
so i determined that i have the old mesa driver

glxinfo | grep 'renderer string'
OpenGL renderer string: Mesa DRI R600 (RV710 954F) 20090101  TCL DRI2

One way to force it is to add in the section Screen

Option  "ForceGallium" "True"

here are my Device+Screen sections (some tweaks are from arch radeon wiki )

sudo reboot
glxinfo | grep 'Gallium'
OpenGL renderer string: Gallium 0.4 on AMD RV710