\override #'minimum-length not working

[David Bobroff]

In the following excerpt I am trying to make the 17 measure rest wide
enough to accomodate the \markup.  I've tried setting this value to
ridiculously large values to try to get a response from Lilypond.  It is
having zero effect.  Am I doing something wrong?

Lilypond 1.7.18 (latest CVS)

-David Bobroff


     quarterStem = \markup \combine
        \musicglyph #"flags-stem"
        \translate #'(0.0 . 3.5) \musicglyph #"flags-u"
     quarterNote = \markup
        \override #'(word-space . 0.0)
        { \musicglyph #"noteheads-2"
          \translate #'(-0.05 . 0.1) \quarterStem }

\score{\notes \relative c {
        \property Score.skipBars = ##t
    \time 2/4
        R2*9
        \mark 24
        \bar "||"
        \time 6/8
        \property Staff.MultimeasureRest \override #'minimum-length = #40
        R2.*17^\markup{\bold \large "Un poco meno" \quarterNote \bold \large "=
100"}_\markup{\number "17"}
        \property Staff.MultiMeasureRest \revert #'minimum-length
        \mark 25
        \bar "||"
        R2.*18^\markup{\bold \large "Pi\\`u moderato"}_\markup{\number "18"}
     }
}