Thats really off topic ^^
I dont know if pushable objects really need physic. It depends on what you want to do. In most cases u can write a "physic fake" which may look better and is much more framerate friendly.
But if you want to use it, your idea is good. But i wouldnt disable the complete physics thats bullshit. Again the manual is your friend.
// disable physics entity so we can manually alter its position.
pXent_enable( me, 0 );vec_set(my.x, newPosition );
vec_set(my.pan, newOrientation );
// re-enable entity, this will inform the physics system that position/orientation has changed.
pXent_enable( me, 1 );