I know is a old thread but i had the same problem and i used this solution.
After the rigid body node, use another Transform Bone node and send the bone scale manually.
Hope this will help others that are struggling with this 
I know is a old thread but i had the same problem and i used this solution.
After the rigid body node, use another Transform Bone node and send the bone scale manually.
Hope this will help others that are struggling with this