Arrow with cross-staff arpeggio

[Stephan Schöll]

Hi folks

What should I do to set a down-arrow to a cross-staff arpeggio? Find 
below what I've tried so far. Neither (1) nor (2a AND/OR 2b) seem to add 
an arrow to the lower end of the squiggy line (in the left hand staff).

TIA for your advice

- Stephan


%%% MWE

\version "2.25.31"

\score {
  \new PianoStaff \with {
    % seems to be added by default in PianoStaff
    % \consists "Span_arpeggio_engraver"
     \override PianoStaff.Arpeggio.arpeggio-direction = #DOWN %% (1)
  }{
    <<
      \set PianoStaff.connectArpeggios = ##t

      \new Staff {
        \relative c' {
          \arpeggioArrowDown %% (2a)
          <d e g c>1\arpeggio

        }
      }
      \new Staff {
        \clef bass
        \relative c {
          \arpeggioArrowDown %% (2b)
          <c c'>1\arpeggio
        }
      }
    >>
  }
}