Fitting adjustable coilovers

Got some adjustable coilovers for my 1990 cabby, fitted the fronts nice and tidy but having issue on the rears. The 2 rubber bushings at the top of the suspension arm, one sits below and one above the top mount and then there is a washer and the bolt. However there is simply not enough thread on the suspension arm for all of that to fit - this is because there is a large metal washer which basically locks down the springs and doesn't allow them to be compressed so you can expose more of the thread. 
Please see pictures as not sure I've explained well - my question is can this large metal washer thing just be removed to allow the spring to be compressed thus exposing more thread and allowing it to be screwed down properly or does it serve an actual safety purpose? 
Thanks 

http://img.photobucket.com/albums/v89/ianscott/Mobile%20Uploads/image_1.jpeg

http://img.photobucket.com/albums/v89/ianscott/Mobile%20Uploads/image_2.jpeg
http://img.photobucket.com/albums/v89/ianscott/Mobile%20Uploads/image_3.jpeg
http://img.photobucket.com/albums/v89/ianscott/Mobile%20Uploads/image.jpeg

You've got it the wrong way around.

The top hat sits on the spring, then the metal collar goes on top then the nut