Disklavier

Sorry if this is a bit 'off topic' but it seems this is the only 
Disklavier discussion group anywhere. 

I've got a Mark IV and hooked up an external monitor today to see how 
the lyrics display worked.  I get the background and the song title, 
but nothing I tried to play actually showed me lyrics.  I know it's 
working as I can change the background from the remote, etc.  I'm 
guessing it's just that very few discs actually have lyrics, can anyone 
confirm?  And does anyone know how to tell which will display or is 
there a list anywhere of those that will work? 

Regards,
Jason