Apparently, despite the fact that Apple added kAudioHardwarePropertyTranslateUIDToDevice in 10.8, it's not actually usable in 10.8, only 10.9. So, instead of being able to use it like a normal, sane person, we have to enumerate all devices manually and find the AudioDeviceID ourselves. A slight annoyance and a mark against apple's competence, but audio devices should now be working again on 10.8 at least, so whatever.