Hm, no I think not :). That is even more difficult.JCMs are slaved to other dials and usually cannot be dialed directly. And they use to make only sense when the figure is posed, and make disturbing results when applied to a zeroed figure.

I added now a tutorial on how to do the M4-to-K4 thing.

http://cgscripts.colorcurvature.com/joint_refitter.html

I used K4 because I think its quite tough. But you can use the same approach to go from M4 to V4 or the other way around. The technique should be usable on any weight mapped figure, though. E.g. Antonia.