constraint angular damping vs. rigidbody angular damping

[catchyid]

hi,
I am using bullet plugin available in maya (i.e. autodesk bullet/maya integration). I have two rigid bodies connected by 6DOF constraint, one of the rigid body is passive and the other is free to move like a pendulum (pls see attached). I locked all linear motion in the constraint so it will act like a point/socket constraint. To damp the lower body angular motion, I changed the constraint angular damping to 1, however nothing happened. When I increased the lower rigid body angular damping to 1, its angular movement was damped.

My question: why the angular motion of the lower rigid body was not damped when I introduced angular damping in the constraint? is my understanding of how constraint angular damping correct in the first place?

thanks...