Just found out, these keys do work in Rhythmbox but only when the window is focused, whenever Rhythmbox is minimized to the notification area, the keys stop working.
-- Gnome CD player isn't controlled by multimedia keys https://launchpad.net/bugs/12178 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
