Attached Link: http://www.nerd3d.com/catalog/product_info.php?products_id=54

NOT for V4 - but Nerd has a free set of "Jiggle" for his V3 walk designer. Link above.

Or you might try and see if renderotica has such an item -

Failing that you could  adjust the right parts mannually in the animation editor.
 

Pinky - you left the lens cap of your mind on again.