Adding right side to volta bracket spanner

[Guido]

Hi,

I’ve been transcribing a modern partiture in Lilypond. I’ve come quite far but 
some details are missing. For one thing in particular I have not been able to 
find a solution. The composer used volta bracket spanners to indicate that a 
group of notes should be played the second time only. To have an accurate 
transcription I would like to show the right vertical line of the  volta 
bracket spanner. How can I trigger that line to be drawn?

----------------------------

\version "2.18.2" 

voltaText = \markup { \text  {2x only} }

Alower = \relative c {

        \clef bass
        \set Staff.keySignature = #`(((-2 . 6) . , FLAT))
        \override Staff.TimeSignature #`transparent = ##t
        \set Timing.measureLength = #(ly:make-moment 4/4)
        
        \cadenzaOn 
        
        r8. 

        \override Score.VoltaBracketSpanner.no-alignment = ##f

        \set Score.repeatCommands = #(list(list 'volta voltaText) 'start-repeat)

        r16 bes'8[ e,16] g,4

        \set Score.repeatCommands = #'((volta #f) end-repeat)

        % Should the vertical line be triggered here? How?

        r8. r16 bes'8[\( e,16]( e[) g,8\) bes'16\( f8]( f16[) e g,8]\) r16  
\bar ":|."
    
    \cadenzaOff
}

\layout {   
  \context {
        \Score       
        \remove "Timing_translator"
        \remove "Default_bar_line_engraver"
        \remove "Bar_number_engraver"
        \remove "Volta_engraver" 
 }
  
  \context {
        \Staff
        \consists "Timing_translator"
        \consists "Default_bar_line_engraver" 
  }
} 

\score {
        
        \new Staff \with {
                \consists "Volta_engraver"
        }
        {
        \Alower
    }
 }

----------------------------
 
Best regards,

Guido