I am looking into this now. My thoughts are, there is support for an audio stream. So if somebody would add an AudioOutputStream as subclass of AudioIODeviceCallback, that would be awesome.
The other option would be to hook directly into OpenAL, which is the audio backend of Unreal.
How buffers are queued is described on page 14: http://openal.org/documentation/OpenAL_Programmers_Guide.pdf
I would be interested, how it went…