displaying composer as artist

[adrian]

I have my classical music tagged with composers and the rest (mostly) tagged with artist. My control point displays only the artist, which I have filled with conductor/orchestra for classical and it is not showing the composer.

I tried

tagCustom=Composer.displayRole={artist}

and I tried

tagCustom=Composer.displayRole={author}

and nothing changed about the display on my control point---I still do not see the composer there. (I don't have do do something special to get changes to take effect, do I? I tried restarting the server.)

I assume I'm missing something simple here. A second question is more complex: can I add composer to the artist display only if the "Classical" genre tag exists?