yep exactly what i said!After looking at the picture I can tell you for a fact that your missing a Black Metal Bracket that goes under the seat lock mechanism. That has the hooks on it for the helmet to lock to. It also provides the proper shim height to the lock mechanism so the seat snaps on properly. That part is about $19.00 from Kawasaki.
There are 2 Phillips screws that hold the seat lock mechanism to the frame. The black metal bracket goes under that seat lock mechanism and is held in by the same 2 Phillips screws.
I can make a pix of it later. But it is missing in the photos posted.