beam-settings for triplets and sixtuplets

[Stefan Thomas]

Dear Lilypond-users,
in the following snippet I changed succesfully the beam-settings for
8th-triplet.
But I couldn't revert it, for the sixputplets.

Here the example:

\version "2.12.0"
AT = #(define-music-function (parser location x) (ly:music?)
#{

  #(override-auto-beam-setting '(end 1 12 * *) 1 4 'Staff)
  #(override-auto-beam-setting '(end 1 12 * *) 2 4 'Staff)
  #(override-auto-beam-setting '(end 1 12 * *) 3 4 'Staff)
  \set tupletSpannerDuration = #(ly:make-moment 1 4 )
  \times 2/3 { $x } \unset tupletSpannerDuration
  #(revert-auto-beam-setting '(end 1 12 * *) 1 4 'Staff)
  #(revert-auto-beam-setting '(end 1 12 * *) 2 4 'Staff)
  #(revert-auto-beam-setting '(end 1 12 * *) 3 4 'Staff)
#})

\new Staff \relative { \time 4/4    \AT { d 8 e f g f e f e d  f e d}
%the beams behave like expected
\times 4/6 { c8 d e f e d } \times 4/6 { e f g a g f} %the beams,
unfortunatley, don't behave like expected
}