Trying to get max & min X, Y and Z values for a btRigidBody

[sregorcinimod]

I have started learning OpenGL and Bullet physics and have started with example code from http://www.informit.com/articles/article.aspx?p=1914612

I have adapted it slightly but only really in what is displayed not anything to do with the physics. But have reached a dead end.

What I want to be able to do is to find out the co-ordinates of the vertices of a btRigidBody during the method:
void btDiscreteDynamicsWorld::updateActivationState(btScalar timeStep)
in the file
btDiscreteDynamicsWorld.cpp

Any help on finding either vertices with the max x, y, z and the min x, y, z would be great.