The Jerusalem Post has an article on messianic 'Jews' in Israel:
"Yes, we believe that Jesus Christ is the Messiah, but it doesn't make us less Jewish than any other Jew," says Noam, another member of the community, and the first non-Russian speaker I contacted. "If Chabad Lubavitch are Jewish, then we are also Jewish. They believe that the Lubavitcher Rebbe is the Messiah, in spite of much evidence that he is not, and they did not stop being Jewish. That is also true for us."
Then again, maybe this is the right approach.