Hi Cyril
I actually looked into this a few months ago and no one makes a projector which can be activated by 24 volt. I couldn't find a D2S bulb in 24 volt either which is the bulb 99% of projectors take. So I don't know how you would go about fitting these. From what I've been told you would have to reduce the power back to 12 volt for everything to operate.
Leave it will with me a couple more days and I'll speak to a couple of retro fitters in the States later today and see if I can get some options for you.
Cheers Mick.