Animating Meta Avatar Hands Through Custom Skeleton

Hello,

Would anybody have any advice for "animating" meta avatar hands with custom, animated skeletons?

I am trying to map Meta Avatar hands to a custom hand skeleton. But as you can see in the img below, the avatar hand is animating very incorrectly. The white hand is our own, is configured with OvrAvatarHandJointType components, and has a skeleton driven by an animator.

I am using a OvrAvatarCustomHandPose to read from this skeleton.

I have a feeling this may be related to the HandSkelLocalForward property in the OvrAvatarCustomHandPose?

Thanks in advance