We know that's a dead end.
Look at http://forums.macrumors.com/attachment.php?attachmentid=208851&d=1262035429 and notice a few things. Such as where the library is and more importantly that item that is checked that tells iTunes to move files around.
I copied ca 40 audio CDs into iTunes on my desktop (Acer Veriton/Vista). The albums all appear nicely in iTunes, but when I check in Sonos on my iPhone only music that was already on my desktop before Sonos was installed appear in the music library. I run a Windows search for one of the songs on my desktop; "no files match your search". The music is there, I can play it on my desktop, but why can't I find it on the harddisk, and why can't I play it via Sonos on my living room stereo set?