Yeah, those snap rings are a big PITA to get out. I have the same hubs on my 88 and have been popping them in and out a lot lately in my axle swap and rebuild, (and subsequent teardown for balljoints after I got it all in the truck /forums/images/graemlins/angryfire.gif.) What I found works well is to get a couple of small screwdrivers, I like the little pocket ones that us PC guys seem to have lying around everywhere, and jam one in about an inch or two from one end of the ring and pry it in towards the hub body, then take another small screwdriver and stick it under the end of the ring and pry out. Then just work the ring out the rest of the way around. It also helps to get the hub body out if you screw one or two the the cover screws back into the hub body and use them as handles to remove the hub body.
Hope this helps.
Sean