hi everyone, just few question about maya grass, I am trying to create realistic grass with maya but I got few problem, need your help, thanks

1- I need the grass only inside the object, inside the plane, but my brush goes outside the plane,
2- it is only can be seen in maya software, not with mental-ray
3- can be applied to the already uv's mapped objects?

I look forward to hear from you very soon

cheers