[Gtk-sharp-list] Painting on the back of a TreeView

[Iggy]

Id like to be able to paint some text on the back of a TreeView, so if
there are no entries it might say something like "No results" on the
treeview, but I can't figure out which code to use. I have tried
painting on the background using a Pango.Layout but it isn;t showing
up. I tried putting it in the Expose event and the Realized event.

Does anybody know how to do this?