How do I force objects to clip without flickering or disappearing?

[panthercom]

 I'm trying to add some light fixtures to an interior cell that will be more than

1/3 buried in the walls or floors. In the GECK I can do this, but in the game

they either vanish or flicker in an out of visibility, depending on view angle.

 I'm also trying to add some piles of dirt that are half buried into the floor.

 

Thanks