nParticle, accurate collisions?

[Forsgren]

I'm doing some previz/proof of concept för an upcoming project, and need to have particles bouncing out of the surface of an object. The particles are instanced geometries (so far just 3 different primitives), and I need the collision to be based out of the geometric information of the instances, as opposed of just the basic spherical collision-cage, so that the particles can tumble over the collision mesh.

I really thought i would be able to do that with nParticles, with all its nice rigid-body-dynamics-integration-goodies. But my google'ing hasn't been very fruitful so far...

Does anyone have any definitive answer whether this is at all possible?