Adding Unavailalbe Song to Playlist

[kaiman620]

I am trying to make a playlist of Pitchfork's 2011 Top 100 Tracks, but ran into a little problem.  I was of course expecting that not all 100 songs would be available on Spotify, but I'd still like to add the unavailable songs (as grayed out unavailable tracks) to the playlist, for accuracy's sake.  I can't for the life of me figure out how to do this, as there's no way that I could find to search for and see unavailable tracks.  Any workarounds? 

Thanks for the help!