Softbody vs Rigidbody CF_NO_CONTACT_RESPONSE

[GLPhysx]

Im trying to disable the collision between a softbody and a rigidbody, I setup my rigid body passing:

rbp->setCollisionFlags( rbp->getCollisionFlags() & ~btCollisionObject::CF_NO_CONTACT_RESPONSE );

But there's still collision when my softbody collide with it... However the other rigidbodies doesn't collide with it.

Am I missing something?