how to judge one object is fully inside another

i use TreeColllision to judge if two object is collide.i use this function CollisionCollide().
but i found if the one object is fully inside another, it returen 0.meaning there is no collide,this is not i want .how i know one object is fully in another?

I've no (simple) idea, perhaps you should ask this in the newton-forum: http://www.newtondynamics.com/forum/

another question, if one collision is just only a plane, when i use OgreNewt::CollisionTools::CollisionCollide(),
it get a error,why?

I would have suspected that newton just doesn't recognize a contact, you should use "reasonable" sizes, so you could make a box out of your plane with a thickness of about 0.01 or so... if collisions are thinner, then other objects often "tunnel" through it.
If you use newton 2.0 beta, you yould also use a HeightFieldCollision ( NewtonCreateHeightFieldCollision ), but there is no implementation of this in OgreNewt yet (though it wouldn't be much work!).