Motor6D animating help

I am currently making sword animations that require a weld to be in the handle of the sword due to the nature of the script belonging to the sword. Putting the motor6D in the handle will cause moon animator to not recognize the handle as an animatable part and prevent me from animating it. Putting the motor6D in the right hand works fine, but is out of the question for irrelevant reasons. What would I do to make this work?