I also used the DIF solution with hot water. . Also , do you use the
paper tiger tool that puts holes in the wallpaper? That helps a lot for
the solution to soak the wallpaper.
The trick is to let the solution do the work for you without letting it
dry to the point that its harder to remove the wallpaper.. First use
the paper tiger, then soak the wall with DIF and hot water. Wait 15
minutes, the soak it again, wait about 10 minutes. Then it should come
off easy. You can find all of the DIF products right he

http://www.zinsser.com/default.asp