OnCollision

I have a dts object (small box) low to the ground. Collision mesh on it works fine. When my player runs on top of the box the player::onCollision() in script does not get called. If the player is standing on the box and jumps the collision gets called. So either the collision mesh for the player for the run/root anim does not penetrate the object and cause a collision but the jump/land does which would make sense or the box collision mesh is to big/small to make it work.
How can I modify the box collision mesh to make the player::onCollision get called?