@Efrint are you trying to make the player have collisions with/effect the newton objects(like in HL2 or Far Cry)?
If you are they way you are doing it is terrible and won't work...
The way you do it the physics properties for the player will not be updated(the physics collisions ect will not follow him). This will result in a player that just falls through the floor.

Instead you have to make a seperate object for collisions and update them in the direction if the player by adding impulses.
Maybe tomorrow I can upload a little open-source demo for you to look at.