accordion push/pull symbols

[Karol Majewski]

Hi,

I'm trying to make my own acordion push and pull symbols. Current LilyPond 
symbols are not that common in my part of the world. So what I have is:

%%%%%%%%%%%%%%%

pull =
#(let
  ((m
      (make-articulation "downbow")))
  (set!
    (ly:music-property m 'tweaks)
    (acons 'stencil
      (lambda
        (grob)
        (grob-interpret-markup grob #{
          \markup {
            \override #'(box-padding . 0) \override #'(thickness . 0) \box {
              \path #0.15
                #'((moveto -0.375 2)
                  (rlineto 0.75 0)
                  (rlineto 0 -2))
            }
          }
        #}))
      (ly:music-property m 'tweaks))) m)

push =
#(let
  ((m
      (make-articulation "upbow")))
  (set!
    (ly:music-property m 'tweaks)
    (acons 'stencil
      (lambda
        (grob)
        (grob-interpret-markup grob #{
          \markup {
            \override #'(box-padding . 0) \override #'(thickness . 0) \box {
              \path #0.15
                #'((moveto -0.6 2)
                  (rlineto 0.6 -2)
                  (rlineto 0.6 2))
            }
          }
        #}))
      (ly:music-property m 'tweaks))) m)

%%%%%%%%%%%%%%%

What I'm trying to do now, is to make those symbols scalable when using:

\new Staff \with {
  fontSize = #-3
  \override StaffSymbol #'staff-space = #(magstep -3)
}

No Idea how to achieve this. I tried to combine my code with the code given 
here:

http://code.google.com/p/lilypond/issues/detail?id=2155

but with no success. 

By the way it would be great to have these symbols included in Feta :)

-
Karol