Oh, ya, the lighting rig is the Skycast demo (which is awsome), I just haven't been able to completely smooth out the shadows. I think that I may just set the Skycast lights to only be diffuse, than use a shadow light with minimal intensity for the shadows. There are 4 lights total- 2 Skycast, 1 specular bulb and 1 diffuse bulb (light yellow color to offset blue hue).
I don't think that Darksim makes a Mac version of thier Simbiont A:M plugin (which I think you need to use the Darktree materials). Perhaps Enhance A:M? Thier might be a Mac version of that plugin?