wet material

Hi!
How can I make a vray-material look wet?
I couldn’t really find something about this, except this tut:
http://www.neilblevins.com/cg\_education/wet\_materials/wet\_materials.htm

but this discusses Standard-materials, I need it for a vray-material.

As the scene is nearly finished I wouldn’t be to unhappy if I could render an extra pass with a materialoveride for the wettiness to comp later on, but this isn’t a must be.

Basicly, a map in the reflection slot, so some areas are reflecting more than others…Or procedural, I did use a Planet Map to make a wet look on asphalt, and it did turn quite nice