I'd definitely use a mix intended for cactus or orchids rather than regular potting soil. Chelle made some very good suggestions. And if you lose a bit of it in the transplanting process, make sure to stick any broken off pieces into some of that same potting soil. Looks very much like the pieces would root nicely.
It IS a cute little plant; it reminds me a bit of the cactus they call "rock plants" except they don't stretch out like that.
And, along with the others here, I'd also like to say