Here are a couple of videos of skinning and how it moves with a walk cycle. I still need to move the bones around, so the legs work properly, but the rest of it seems to be ok.
Import the mudbox man into 3DsMax and turn him see through. You do this by selecting him, and go onto object properties, then hit the see through button. You then go onto create, helpers, then go down to the cat objects. Then hit cat parent and go down to the base human, and drag him up to the mudbox man. You then move and scale each bone to the required length, so every bone sits nicely within the man. Then you select the man and go to modify, and go down to skin. This creates a skin around the man, using the bones that you have selected. You go to add bones, and add all but the base human and base that he is standing on. You have now got a skin around the man. You can then go to motion with the base human selected and create a motion using the ABS key, hold it down and select the run cycle. Then hit the circle key with the stop sign in it, then press play at the bottom, and you can see if it moves seamlessly or not. You can then go back before the skin modifier to tweak it until it works. Then save it!