How do you change the search location of the Music Lens?
Solution 1:
It shows what is inside Banshee's database so you could update this. How to register downloaded podcast mp3 in Banshee? probably answers how to do that.
You can also symlink your music directory. That way anything thinking it should look in ~/Music/ will look in your folder.
You can do that like this:
cd /home/username/
mv /home/username/Music /home/username/Music.old
ln -s /your/path/to/music/ Music
You can just remove Music or Music.old if you don't need it.
I assume that rescanning the folder would add them to your database.