I am restoring a 65 mustang and I am trying to install a new trunk lock.  I think I have everything but when I put it all together the lock still moves around and the extension then comes out of it's spot.  It seems that I am missing something that should hold it in place.  I can't seem to find anything that would do this.  Does anyone have any ideas as to what it is that I am missing or doing wrong?  

From rear to front: outer lock sleeve, gasket, trunk lid, spacer sleeve, washer, nut and lock extension bar, latch. (If you need to know what these look like go to page 40 in the NPD catalog).