[ODE] Sphere-trimesh collision detection does not work

[Pawel S]

I have a fixed and bodyless trimesh 101x101 squares/units large (Hoping
to implement larger terrain later). A vehicle made out of a box and four
spheres driving on the trimesh uses spheres for wheels as collision
geoms. The geoms sometimes penetrate the trimesh leaving the body geom (a
box) resting on the trimesh.
What is the matter? What is the state of the trimesh-primitive collision
detection code. Can I use other geoms that do work? If the code is ready,
then what are the best practices for implementation? I appreciate any
help.

Pawel