@odf,

Your "MouthOpenActiveSwitch.pz2" should work as far as it goes, but it looks to me like it just deactivates the morph (I haven't tested it in Poser). I think Cage wants a way to deactivate the slaving without deactivating the morph, or jaw rotation.

I'v been up a long time and, I'm tired, so perhaps I am not seeing things clearly, but I can't see a way to do what cage wants, without slaving "valueParm JCM-MouthOpen" to the MouthOpen channel, instead of the xrot channel. In fact its being slaved to xrot does not make much sense to me.

The above file seems to do what cage wants, it adds a dial to break the slaving, but at the price of changing the slaving relationships. I don't see what harm applying this pose could do, but then I don't know your reasons for setting up the JCM the way you have, and perhaps my pose will mess things up in some way.

Perhaps tomorrow I will be able to see things more clearly. Perhaps I will be able to think of some other way to do it.