Thank you for your time .
It doesn't matter if I change the lights, is allways the same. I have changed the pasted material (is the whole glass what was pasted), but is the same. Also I have played with the reflection and refractions in the mental ray settings but I keep getting this:
In other animation a ball pass behind the glass with the same effect, proof that the guilty is not the pasted material, but the look is not so unrealistic:
I am beguining to think that perhaps it cant be done using this material. I dont know.