(T) Stilo Multiwagon Rear Window

I have just had a problem with the rear window on my Multiwagon. 2003.
The catch which secures the window closed and is stuck onto the inside of the glass has fallen off and I now cannot lock the window. Fiat has washed their hands of this obvious design fault. I understand their is an upgrade to this problem and there is also another window which has the glass fitted into a frame. Has anyone come across this problem or knows anything about the upgrade or the alternate window in frame.