Note: I you already removed the disposable housing before reading this section, don't panic! This is how we install the housing at the factory:
Put a 45 degree kink about three inches from the end of a piece of stiff wire (brazing rod if you have it, although a wire coat hanger will work) and thread it through the tob tube, watching at the far end of the tube. When you see the leading end of the wire line up with the hole in the top tube, twist the wire until the kinks pops through the hole. Then thread your housing over the wire.