I suggest putting a 10 second delay relay on the HID. When you turn on the key, the light turns on. Hit the starter, and the voltage feeding the igniter goes to the threshold of acceptable. Sometimes below. This turns the HID light off and then immediately restarts it. Not good for the longevity of the bulb. In the more expensive HID units, this isn't as much of a problem. The inexpensive units from China (sold by Canadian Customized Cruisers and others) will have this difficulty.
FYI - I have a cheap CCC HID. It has lasted several years and many 10s of thousands of miles with the 10 second delay relay. The bulb would last about 1/2 a year before installing the time delay. As an alternative, install a manual on/off switch for the headlight. Just make sure it is off when you start the bike.
RR