http://picasa.google.com/support/
It's probably your best bet as this forum is primarily SketchUp. Some here might know but in the mean time you could try the link above
I put them in the M under Perpendicular in Fresnel Reflection. The S is a specular map and tells the material what parts reflect less/more than others. Example, a tile's grout would not reflect much at all, if any, so the grout lines would be almost black.
Arrowway rocks BTW - good investment!
Also you need to set your field of view to 1. You wont be able to rendering a true elevation with vray but a FOV of 1 is not noticeable as a perspective.
