How can I change the dimensions of collision volumes showed in UE4's physics asset tool?

How can I change the dimensions of the capsule for one bone in the physics assets tool?

The problem is that bones not connected by joints have overlapping collision volumes in the mannequin that comes with the starter content, which causes those body parts to apear dislocated or out of place when the simulation is running.

For instance in this image the pelvis and the middle bone in the spine (Spine 2) are overlapping.

So, when the simulation runs Pelvis and Spine 2 get pushed apart reducing the overlapping to a contact point.