Vray environment fog problem

[netnerd]

I am currently working on a swampy environment using maya and vray as the renderer,,,i studied up the vrayenvironment fog shader and apllied it to the use environment slot in the render settings,,but i get no results/no volumetric effects none what so ever,,not even a pitch black or a heavy fog for me to tweak or to apply noise to....

vray works well for everything else,,,but i dont seem to get any volumetric effects?
Is there some setting i have to enable for them to render properly in MAYA 2011?

please advice....

thanks...

[netnerd]

wrong thread!,,,my bad....but if any1 knows the solution,,plz advice...