As you've used Arena, how does the armature setup work? Is there a default in-application skeleton to map the pointcloud on, or can you import the rig from the mesh you intend to mocap for? I'm in the midst of scripting myself, and looking hard at Arena to speed the process. But one of the issues still with Poser is the rigidity through the torso. Getting a figure re-rigged with more spinal bones will fix that, but if the Arena software won't accept it, it wouldn't be worth the time and effort (plus the cleanup could be a nightmare....).