Configurable Joint AccelerationDrive Flag

Trying to get Configurable Joints to behave as predictably as possible. I have them working reasonably well. My current understanding is that the Configurable Joint is essentially the PhysX D6 Joint exposed in Unity. Unity's Documentation on the joint is somewhat lacking, so I've been using Nvidias Docs instead.

http://docs.nvidia.com/gameworks/content/gameworkslibrary/physx/guide/Manual/Joints.html

Those docs list an AccelerationDriveFlag thusly : "acceleration drive flag. If this flag is set the acceleration (rather than the force) applied by the drive is proportional to the angle from the target."

This would be insanely useful. My current use case is an Active Ragdoll system. Many of these exist and they're all acceptable, but exposing or mimicking the above behaviour would produce far more reliable, if less physically accurate results.

If this is already exposed somewhere and I'm missing it, please point me there Immediately. Otherwise can I request it be exposed somewhere?