fretboard diagram : alignment issue

[Marc Mouries]

Hi Lilyponders,

I am trying to generate a chord chart for Violin and i have an alignment 
problem.

I want to include the different possibilities of playing a chord and 
thus i can't use the command storePredefinedDiagram and thus can't use a 
FretBoard like this

\score {
  <<
    \new ChordNames { ...    }
    \new Staff { ... }
    \new FretBoards { }
  >>
}

But i have to use

<<
  \new ChordNames { \chordmode { d1 } }
  \new Staff {
    %% D
<d'  a'  fs''>2 ^\markup \fret-diagram #"w:4;4-x;3-o;2-o;1-2-1;"
<d'  fs' d'' >2 ^\markup \fret-diagram #"w:4;4-7-4;3-4-2;2-5-3;1-x;"
    %% D7
<d'  c'' fs''>1 ^\markup \fret-diagram #"w:4;4-x;3-o;2-3-2;1-2-1;"
    }
>>

Which gives me:

Is there any way to align the fret board using markup? or any other work-around 
to be able to use a fretboard and use several definitions for one chord?

thanks,

Marc

Based on this snippet: http://lsr.dsi.unimi.it/LSR/Item?id=578