Humanoid IK Not Working With Extra Twist Bones on Limbs?

I have imported an advanced rig model from MakeHuman with their face rig and extra twist bones. I haves set it up as Humanoid. The arm chain is UpperShoulderTwist01[Humanoid IK chain] -> UpperShoulderTwist02 [skipped for IK] -> Elbow [Humanoid IK Chain] -> ForearmTwist [skipped for IK] -> Wrist. I have a single animation that is the default pose looped for one second and IK pass set on the only layer, layerIndex is set to 0. The goal strength is 1 on all IK Goals.

I assumed Unity could handle extra twist bones if you set up the rig, forced TPose and all the hierarchy was correct down chain. Did I make a fatal assumption or am I missing something? I need to make an entire procedural IK control system and this throws a monkey wrench in the gig.

 

I think you can override mecanim, however it must be implemented in parent bones order to get its effects with children.
Use LateUpdate to make the ik effect by manually updating the transitions.

 

Problem was IK would not work. I made a standard rig that did work and added parallel to wrist child twist bones on the forearms and the IK worked..so..big mystery still.

 

Are you using MonoBehaviour.OnAnimatorIK(int) as an example of how to interact with the engine?

 

Yes..same way I have been using it since 2013 except I ha twist bones in it from MakeHuman so I could get the face rig armature. Figured the IK chain would just work if I configured he avatar correctly. I tried every config and no go with IK..