Right, don't currently have my wolf shoulder rest, but here are a few pictures of my chin rest and how it attaches to the violin. I'll also put the urls just in case the pics get deleted by the moderators at some point.
N.B. moderators, these are very low res images so even though they appear large I don't think they'll use up much bandwidth.
this shoulder rest is at least 15 years old - I've had it longer than my violin - or indeed any other instruments I own except perhaps my descant recorder!
http://img.photobucket.com/albums/v172/sar...wolfmastro1.jpg
the top view, you can see how it crosses over the tailpiece
http://img.photobucket.com/albums/v172/sar...wolfmastro4.jpg
again, you can see how it goes over the tailpiece. the flat of material that comes down to cover the metal parts is rather worn through! you can also see how thick it is especially at the section where it passes over the shoulder rest. it's also much wider than most wooden or plastic rests, and the cover is a soft "faux-leather", which is very comfortable.
http://img.photobucket.com/albums/v172/sar...wolfmastro2.jpg
this shows the violin with my current shoulder rest, it isn't perfect but it's passable with the chin rest.
http://img.photobucket.com/albums/v172/sar...wolfmastro3.jpg
This shows how the rest attaches to the violin - because it only has one bar that comes down, it gives great flexibility of position and angle. It holds very firmly, I've never had it fall off or anything.
http://img.photobucket.com/albums/v172/sar...wolfmastro5.jpg
The silver bit is the screw that holds the rest in place, it's openable with a little screwdriver of the sort that often comes with adjustable shoulder rests/chin rests - mine says "wolf" on it and I believe it came with the chin rest.
Don't get me wrong, it ain't cheap - but it's certainly worth a try. I struggle to play on a violin or viola with a normal chin rest - have problems holding it firmly, neck ache, etc. Really worth giving one of these a trial, I know it has helped me a great deal over the years. And it's lasted well too! The rest is designed to fit any violin from very small to a big viola - they claim 1/4 size up to "biggest viola", and I certainly had mine from 1/2 size upwards. It's also easy to remove and replace, so if you play viola too that's a bonus.
Anyway, I'll stop advertising for them now

but I do recommend having a try with one if you possibly can.