vray and displacement on a bottle surface

[syokaku]

hi everyone,
I modeled a bottle, now the client asked to me to put a logo beveled on the glass surface of the bottle. I thought to use the vrayDisplacementMod but I don't know how to use the map in the right way: I need only one logo on the entire bottle surface and I need it in a certain position on the bottle surface –*I need something similar to a uvw unwrap applied to the vrayDisplacementMod.
Is there any possibility of doing this?

thanks in advance.