Thanks folks.

I suspected that but didnt find a relevant info in the manual- stupid that the CyclesSurface has the "Firefly" radio checkbox. So you can switch it on but it doesnt render.

Stiff like that can drive you crazy, when you spend hours to figure it out-

Meanwhile I found that you can use the shaders in PoserSurface, when you feed them into a Blender node first. Then you can send this into a step function etc. So I got my posterize effect, will post images later or tomorrow

It seems a little bit slow to render though, not sure why, its not even raytracing.