Proper Setup Of 3 Axis Rotations Using BlendTrees and Layers

Mecanim should have a 3D BlendTree. I am trying to use it to rotate a hand IK Object to avoid pinwheeling with a Bend, Flex and Twist parameters that are animations using the hand's natural limits. Bend is an X rotation, Flex is a Y rotation and Twist is a Z rotation. They are all set to the range -1.0 to 1.0 wioth 0.0 being Neutral. I have tried setting the Bend and Flex on the BaseLayer using a 2D BlendTree with X of course controlling bending and Y controlling flexing and on the second layer I have the Twist BlendTree. To start with in runtime even though the values change for Bend and Flex which are in the Base Layer they do not do anything at all though pulling the Bend and Flex sliders in Editor mode shows the hand doing what it should. The only thing working is the Twist on the second Layer when Weight is at one and set to Override and again the BaseLayer Bend and Flex animations do not work as advertised. In Additive mode on the second layer Twist does nothing whether Sync is checked or not.

So the question is how do you set up a controller so that you can access three different rotation axes and blend them accordingly?