But this application is supposed to allow you to stream online. How I want to send a finished movie is a different story. It is about online stream. If Facebook requires aac then it should be aac and not mp3 ...
It does a LIVE stream to stream online. I suppose you could connect it live and then play that file back from inside VEGAS Stream.
VEGAS Stream allows to you to LIVE stream to Facebook while also capturing everything to allow a post edit afterwards. The capture of audio is MP3 which you would then use in your post edit and then you can render that from VEGAS to any format you want - including AAC if that's what you want.
If you want that post edit uploaded, you would then just upload it the same as any other file you upload. Facebook doesn't require an AAC file to upload.