Just had the same problem-ish. Left side came off easy enough with the standard four taps, North, South, East, West. I changed the shoes and then went to the other side and could not get the darned drum off! It occurred to me that the new install on the left side was putting pressure on the right side so I went to the left side and pulled the cylinder sliders out a bit with plyers. Wouldn't you know it, the right side darned near fell off :D
Then I screwed the pooch by completely pushing the right side cylinder out on one side and draining the fluid. There are many four letter words for such things so fill in the blank. Why, are I a complete ____ !
Now I'm going to pay someone in overalls to unscrew my pooch and spend all the money I saved by changing my own back brakes. Why don't all vehicles have discs all round... it's 2009, for the love of Dale!