standard AV-out works on GTA04 already afaik. We might not have the automatic detection and replace that by a requester in userland, to select what type of cable you attached resp which function you want to use (headset or AV-out) - after all that detection never was really great on N900 either. MiniHDMI is a completely different topic which starts with "where's the apperture for that in N900 case?"