I've tried it again, in Poser 7 this time, and it still works. Screenshot attached, you can see in the Hierarchy editor that the hands are parented to the balls.

You have to switch on Inverse Kinematic before you parent the hands to the balls. If you move the balls and the figure moves then you have parented the body of the figure, not the hand. 

A ship in port is safe; but that is not what ships are built for.
Sail out to sea and do new things.
-"Amazing Grace" Hopper

Avatar image of me done by Chidori.