But a new problem arised:
Particles do not drop shadows on other particles. They also don't get the correct shading from final gather.
So I continued reading. I've read that I can also correctly shade particles by using segmented shadows. Fine. However, I need to create a mi_trace_shadow_seg node to get it working this way.
But I can't find this node. I looked into the node list from top to bottom and from bottom to top. But it isn't there.
Is there another way to create this node (if it exists)? The documentation isn't a real help when i work with maya.
The other way would be final gather. But final gather also doesnt really take note of those particles. They are just shaded from the environment.
At the moment I use AO as a solution but the result is also not the best. :/