P.S. If you don't beleive what I said in my last post, try the little pp2 attached above. Its yrot channel uses 'forceLimits 1'. Its 'zrot' channel uses 'forceLimits 0' (=limits not forced). Its xrot channel uses 'forceLimits 4'. The above file only has rotate channels, the other channels have been stripped out to save space.

Nothing you can do from the Poser interface will un-force xrot or yrot.