Never had to do these. In reading the manual there are (3) special bolts that need to removed with regards to the drum. In the past, other drums (can't recall of front or rear, all one had to do was de-adjust the shows and vibrate/pry off the old drum.
The only thing that I ever saw holding the rear drums on was two Tinnerman nuts, and these are usually long-gone, unless you have a hard-core show car.