So here's a small photo story of how to refit a BG 1700 cover (sorry for the bad quality):
First of all, assemble the parts as shown in the photo - thats the easy part.

Now attach the middle holder, but don't tighten the screw completely (but almost completely).

Then force the left end of the spring back into his channel (or however you call that thing in english - I hope you understand what I mean). By the way, that yellow stuff in the picture is glue - I had to reattach the three metal brackets.

Then attach the holder there, tighten the screw completely; do the same thing for the right end of the spring; tighten the middle holder completely, and you're done. 
