Quote - "The one that is useful and which no other program can replace for you is the Multi-Pass rendering."

Actually ren_mem Poser has had Render passes for a long time now.  It's under "Scripts".  I only have Poser Pro on this computer, but it even allows you to select how you want your shadows handled (ie separtate passes).

I've used it for a few things, it is a handy little feature.

I didn't mean no other program had multi-pass. That would be silly to say. I meant that if you are using Carrara as your renderer then a multi-pass feature isn't something another program can do for you. It needs to come from the rendering program not outside the rendering program.

Regarding the poser shaders. I agree. In fact, the more you do in Carrara, the happier you will be. It's a paradigm shift. Anytime you have to go back and forth between programs it can be a pain. Integrated program suites like adobe's are a good example of making that much easier.

No need to think outside the box....
    Just make it invisible.