Smooth avatar match pose from body tracking to animation

Hi,

I'm trying to switch smoothly from live body tracking (applied to the avatar) to an animation. I tried to make this smooth transition using this: http://docs.unity3d.com/Documentation/Manual/TargetMatching.html and this https://docs.unity3d.com/Documentation/ScriptReference/Animator.CrossFade.html, but as I don't start with an animation it always jumps.

I thought of just going bone per bone slerping the orientation of the ones I get at the beginning of the transition and the ones of the first frame of the animation, but I can't see any way of accessing the animation values.

Does anyone have an idea of how to solve this?