I've got a scene which uses Physical Sun and Sky, and when I try to connect the sky node to the mental ray volume shader in the camera to create a fog effect, everything works (including the fog), but none of the nParticle balls in the scene will render. When the volume shader is disconnected, the nParticles will render again, but if anything is connected to the volume shader the nParticles disappear again. I've read that there might be compatibility issues with Mental Ray and nParticles, but other than that I haven't been able to find anything to fix the problem.

Any help with this problem would be appreciated!!!