Haven't tried it myself, but I would suggest not to bother. It's more than likely to seize up really, really well, and once that happens getting it out is going to be a mission and a half (not to mention the risk of damage to the frame in doing so).
sorry but thats just BS! I know of a ti headset on a ti frame since 99 with 0 problems. the ti into ti problem is for threads where the ti "galls". with a frame & headset obviously theres no threads. I've seen both antiseize & weak threadlock used for the cup/frame interface, on a moots ti roadbike & a yeti arc ti, 1 of which has had over 8yrs use, again with no problem