I believe it’s a Flash limitation….so, no.
The only way it’s ever going to do anything besides mp3 (i.e. aac or flac), is if Flash ever starts supporting formats besides mp3 (not very likely) or for Firefly to transcode to mp3. Has been some discussion of that in these forums (like maybe transcoding to mp3 for specific ip’s or clients), but it’s really not there at this time, unless someone were to try and hack something together using ssc transcoding. I don’t know of anybody really playing with that to date.
I played with Fireplay, cause it’s pretty cool being able to stream from Firefly through my Wii. But alas, most of my library is aac and flac…so it’s really not much use for me at this time.
Not sure of other options. I also played a bit with Orb (which is a web-based UPnP server, requires a Windoze PC that’s always on). It works ok, but is a bit buggy at present. Client streaming is also with Flash, but with proper codecs, will play both aac and flac transcoded to mp3, but doesn’t really understand their tags at present. So again, for me, of limited utility.
Also used SlimServer many moons ago. Another UPnP server that IIRC can run on either Windoze or Linux, and transcodes everything to mp3 for http streaming if proper codecs are installed.