Cross staff stem breaks

[Pierre Perol-Schneider]

Hi List,

This question comes from the Franch list:
http://lilypond-french-users.1298960.n2.nabble.com/Hampes-changements-de-portees-accords-arpeges-td7584149.html

Bernard is trying to reach this output:
http://lilypond-french-users.1298960.n2.nabble.com/file/n7584149/exemple_cross_staff.jpeg

Here's what I propose:
\version "2.18.2"

\layout {
  \context {
    \PianoStaff
    \consists #Span_stem_engraver
    connectArpeggios = ##t
  }
}

{
  \new PianoStaff <<
    \new Staff \relative c'' {
      \key b \major
      \time 3/4
      <<
        \new Voice {
          \voiceTwo
          \shiftOnn
          <e b' e>2 <cis e fis cis'>4
          <dis fis dis'>2
        }
        \new Voice {
          \voiceFour
          \override Stem.cross-staff = ##t
          \override Stem.length = #14
          <e, b'>2\arpeggio fis4\arpeggio
          <fis b>2\arpeggio
        }
      >>
    }
    \new Staff {
      \key b \major
      \clef bass
      \time 3/4
      \new Voice {
        \voiceFour
        \autoBeamOff
        \crossStaff {
          %% does not work (not surprising):
          %\override NoteColumn.force-hshift = #1
          %% workaround:
          \override NoteHead.X-offset = #.75
          \override Stem.X-offset = #.75
          \override PianoStaff.Arpeggio.extra-offset = #'(-.75 . 0)
          <gis b>2\arpeggio ais4\arpeggio
          b2\arpeggio
          \revert NoteHead.X-offset
          \revert Stem.X-offset
          \revert PianoStaff.Arpeggio.extra-offset
        }
        \autoBeamOn
      }
    }
  >>
}

Question:

Is there a way to reach the picture without my workaround?

TIA,

Pierre