Attach footnote to barline?

[Nick Payne]

Can a footnote be attached to a barline? This works fine for the note 
but not for the barline either way:

\version "2.15.30"

#(set-global-staff-size 30)

\relative c' {
    \footnote #'(0.5 . 5) #'NoteHead \markup { NoteHead }
    c4 c c c
    \footnote #'(0 . 2) #'BarLine \markup { BarLine }
    \bar "||"
    c4 c c c
    \footnote #'(0 . 2) #'Staff.BarLine \markup { BarLine }
    \bar "||"
}