problem with svg-output

[Stefan Thomas]

Dear community,
when I compile the following file with 
lilypond -dbackend=svg
the svg-output looks different to the pdf, I've compiled with lilypond.
The symbol for "muchair" is not displayed correctly.
Here the example:

\version "2.14.1"
%%%%%% note with air

#(define (airohalf radius height thick)
    (string-append "gsave
                    /msellipse {
                          /endangle exch def
                          /startangle exch def
                          /yrad exch def
                          /xrad exch def
                          /y exch def
                          /x exch def
                          /savematrix matrix currentmatrix def
                          x y translate
                          xrad yrad scale
                          0 0 1 startangle endangle arc
                          savematrix setmatrix
                      } def
                    /rad " (number->string radius) " def
                    /offset " (number->string height) " rad mul def
                    /ecenter 0 offset add def
                    /xradius rad rad mul offset offset mul sub sqrt def
                    /yradius rad offset sub def
                    " (number->string thick) " setlinewidth
                    currentpoint translate
                    0 0 moveto
                    newpath
                            0 rad rad 0 360 arc
                            fill
                    0 rad translate
                    1 1 1 setcolor
                    newpath
                            0 ecenter xradius yradius 0 -180 msellipse
                            closepath
                            fill
                    0 0 rad sub translate
                    0 0 0 setcolor
                    newpath
                            0 rad rad 0 360 arc
                            stroke
                    grestore"))

#(define (airuhalf radius height thick)
    (string-append "gsave
                    /msellipse {
                          /endangle exch def
                          /startangle exch def
                          /yrad exch def
                          /xrad exch def
                          /y exch def
                          /x exch def
                          /savematrix matrix currentmatrix def
                          x y translate
                          xrad yrad scale
                          0 0 1 startangle endangle arc
                          savematrix setmatrix
                      } def
                    /rad " (number->string radius) " def
                    /offset " (number->string height) " rad mul def
                    /ecenter 0 offset sub def
                    /xradius rad rad mul offset offset mul sub sqrt def
                    /yradius 0 rad offset sub sub def
                    " (number->string thick) " setlinewidth
                    currentpoint translate
                    0 0 moveto
                    newpath
                            0 rad rad 0 360 arc
                            stroke
                    0 rad translate
                    newpath
                            0 ecenter xradius yradius 0 -180 msellipse
                            closepath
                            fill
                    grestore"))


#(define-markup-command (airytone layout props radius height thick)
   (number? number? number?)
   (let ((longstring ""))
     (set! height (max (min height 1) 0))
     (if (> height 0.5)
         (set! longstring (airohalf radius (* 2 (- height 0.5)) thick))
         (set! longstring (airuhalf radius (- 1 (* 2 height)) thick)))
     (ly:make-stencil
      (list 'embedded-ps longstring)
      (cons 0 0) (cons 0 2))))

muchair =  \markup { \airytone #1.0 #1.0 #0.1 }  
motiv =  { \times 4/5 {a32-.->\f [ b-.  c'-.   cis'-.   d'-.   ]} }
\new Staff {
  \override TextSpanner #'(bound-details left text) = \muchair % der Text, mit der TextSpanner beginnt
r2 r4 r8  \context Voice << {\motiv} {s8 \startTextSpan  }>> \times 4/5 { cis' 32-.   d'-.   es'-.   \stopTextSpan   r16   } r8 r4 r2 
  
}