Decal problem with vray in Rhino

[palosanto]

I'm new to v-ray. I'm using Rhino and I used Flamingo previously for most of my work.
Basic question (or is it?)

To put it simple, how do I apply a decal to an object, say a sphere, without going through to the other side and without splitting the object in two?

In Flamingo I place the planar mapping widget somewhere inside the sphere and tell it to project towards the front, so the image shows up at the front of the sphere but not at the back.
But in vray I don't seem to find a way to limit the projection of the decal to only one side of the planar map so it always shows on the other side (mirrored of course)

I can't believe it, I've posted this question in many forums and I can't get an answer ...
I use rhino but the solution probably applies also to Sketchup)
Any ideas? Here are some screenshots