2.5 smoke modifer

i tried a sample file with smoke modifer
which is using voxel

and i tried to change text specs and intensity ect

or change some of the mat spec but nothin seems to change the density of the smoke
brought the density close to zero but no change at all !

i ran with Alt-a to see it and looks all the same very dense and dark
cannot also change the coplor of the smoke

has this feature been implemented at 100 % or still buggy ?

any ideas her how to change th smoke density and color