there is a howl package, but i have no idea how to use that thing! 😉
Should be able to install the howl package and set a mDNSResponder.conf (int /etc/howl?) that looks like:
My-server _rsp._tcp local. 3689
My-server _daap._tcp local. 3689
Then run the mDNSResponder and it should show up in iTunes, even without mt-daapd running (course, you won’t be able to connect…)
Then start mt-daapd with the -m argument, and it will not try to advertise mdns.