Grass particle help

Hi there,

I am making my first game which is going to be a fps based on the war between the british army and the zulu. Anyway I am having trouble placing grass on the terrain. I have made a object with a grass texture and alpha channel and I want to ‘paint’ the object onto my terrain using the particle system. I then want to convert them back to objects once I am done.

My problem is when I am painting the object onto the terrain, the grass plane paints now were near where I am painting. It also does not appear on the same level along the terrain it appears much higher. Waht setting do I need to change to it just paint where I am painting and also just paints along the terrain not above it?

p.s In the screen shot, the light pink area is where I painted the particles and the dark Is where the actually appeared.