is there a trick to propagate and plant christmas cactus?

It's one of the easy ones. I do it in water: twist off cuttings of two or three segments, let them dry a day, then stand them in a glass with just the bottom tip in the water. Roots in a couple of weeks. When the roots are an inch or so long, pot them in a gritty cactus mix - put four or five cuttings in one small pot rather than one each, and you get a full-looking plant in a year instead of a lone stem.