I'm not quite sure
http://fsdeveloper.com/forum/forumdisplay.php?f=87
http://www.fsdeveloper.com/wiki/index.php?title=ModelConverterX
It comes with a licence which prohibits hacking other's work.
I doubt very much that it was designed with hacking others' work in mind. It's developer is a leading developer of MS scenery add-ons and an MS MVP.
There is another utility that works with Blender. I believe it's a bit limited too. It's been mentioned in various dev forums too.
I always think it's a good idea to start models afresh if one accidentaly trashes one. The result is usually much better than the original and does not take much longer then converting an old model. I can see the benefit of this type of tool if one wants to update an old FS2004 scenery project to FSX standards.
Ah ok, thanks Rob, I missed that one.
Still I don't see why such a tool should be publically available.