I'm trying to add a briefcase nuke using the briefcase detonator, and it basically floats wherever I drop it. How can I get it to fall to the ground like any other mine?

http://i9.photobucket.com/albums/a96/The_mango55/Games/floating.jpg


Another question, how can I merge objects in NifSkope to a current object's havok model? I know how to add them onto an object but in game only the main model moves while the other things are static.

Or do I have to do it with 3ds max? If so, how?