Hi, this is a friend of Farsthary (he has currently less resources, so he can not get connected during a while…)
The great Matt Ebb has been porting the volumetric code to the new blender 2.5 sources (this blender version should comes in October), and it has just been merged!!
Kudos to him!!
(Go on blenderartists if you are looking for some help)
p.s: I will send soon a cd with the new source code to Farsthary so that he can keep updated with all these new stuffs