Mine works on the XTZ. On my 06 I had to adjust it a couple times, but that made it work just fine. They do stay in adjustment longer if you don't drive around with the parking brake on.........................
I broke mine initially by leaving it on and driving (Doooh!) That just required a pad change. Then, my friend borrowed it and did the same thing. It also developed a siezed piston and stretched parking cable, so I replaced the parking cable and the entire brake assembly. Works fine now. Also replaced the rotor - around $50.
For the guys that have one that doesn't work, where are you guys adjusting it?
I tried to adjust the cable first but it still didn't hold. I then loosened the cable, moved the arm on the caliper one notch, then adjusted the cable so it worked good. Like I said earlier, no problems now. (and I never drove with it on )