Without knowing anything more specific, it's hard to think of a more elegant solution than just wiring the z Axis. Transform locks are only meant to lock the transform from direct manipulation by the user. I tried a couple of things here: https://dl.dropbox.com/u/2904948/Tutorials/WireZ.max The setup on the left is using a…
I'm gonna go out on a lim here and say look in the motionn tab. there should be a check box to limit the roation to only Z. Though it may only be what in inherits instead of it's own transformations but I can't remember. Also look into contraints I'm sure in the motion tab in the little list box if you go under roation and…