Put this at the Blender.org site but decided to here as well.
Wrote up a paper on hand editng a .osg file exported from blender. Currently you get a mesh and a 24 bit texture.
This paper tells how to edit in for 32 bit alpha, lightmaps, two sets of UV and other junk (Basically stole from 3dsMax's exporter the info).
Decided to post to a couple of Blender sites in case others are using, and in the hope someone might find the information useful in fixing up the exporter to handle these things themself (Don't know Python, don't want to know).
Since some of the effects merely mean adding a few lines or copying and pasting info, a few check boxes and input windows might add up to a bit more functionality for the exporter.
And if nothing else you can read the new Blender paper that goes along with it on how to do burnin maps.
found here as a PDF in the artist section near the bottom.