Best way to export FBX Humanoid with props

I have to export an humanoid with a prop in his hand, and during this animation the prop falls into the ground.
What is the best way to export this?

For example:
* Export the skeleton animation with an empty transform T parented in the right hand: this transform will set my prop position and orientation.
* When the prop falls down, the empy transform (T) remains a child of the right hand, but translates over the ground.
* When importing into unity, I add the prop object as a child of the (T) empty transform, and everything should work.

Is this correct?
Thank you

 

anyone?