UnitySteer and physics collision

Hi everyone!
I have some character controllers using unitysteer’s vehicles and steering behaviors. They work ok. I need they to collide each other, but no OnControllerColliderHit or OnCollisionEnter events are triggered. It looks like they are stopping just before collide, even if I disable the obstacle avoidance and evasion components and reduce the vehicle’s arrival radius to 0. Does anyone knows how to deal with this?

I had a similar problem with unitysteering rigidbodies, but it turned out I was using OnTriggerEnter when I should have been using OnCollisionEnter.
Your problem sounds like the same as this: http://answers.unity3d.com/questions/14427/charactercontrollers-dont-register-collisions-with.html