edited January 2014
I came across this open source program. (
) It looks great to work with Millumin!!!
Could it be "tweaked" to output to Millumin?
For now, it's not possible to get the output of MusicBeam into Millumin (you can try with Syphoner however).
But as this software is based on Processing, it could be very easy to add Syphon support on OSX : you should ask the developers.