how to get object moves along with certain body parts

[dcsfz]

Hi everyone, i encountered a small problem when editing a mod. i ported a sword from elsewhere, however i couldn't get it to move with the hand in game, it sticks to the body. i tried assigning the sword to arm vertex groups in Blender to no avail. 

 

I'm pretty new to modding and i know this is probably a easy cake for seasoned modders out there.

 

any help would be greatly appreciated!

thanks