Very long hyphens in lyrics

[Erik Sandberg]

Hi,

I'm typesetting a piece where the first syllable "dam" of one word "dam - ni" 
is ornamented for 3 bars. I am no expert in vocal music notation, but all my 
sources notate this by using a sequence of short hyphens ("dam - - - - - ni" 
like LyrB below) instead of one very long hyphen ("dam     ----     ni" like 
LyrA below). However, my hack in LyrB is an ugly hack that shouldn't be done.

Is there an easy way of achieving something similar in Lilypond? If not, 
should there be one? (Since this seems to be some kind of standard, perhaps a 
special notation of it would be motivated? E.g., --- or -- --?)

Thanks,
Erik

\version "2.0.1"

Not = \notes \relative d' {
  \time 3/8
  \key d\major

  \partial 4 e8 a |
  fis16 e fis g a b |
  %30
  e, d e fis g a |
  d, cis d e fis gis |
  a8 e cis' |
  b16(  a) gis4 |
  a4 r8 | 
}

LyrA = \lyrics {
  no8 -- stri dam8*10 -- ni8 cau -- sa __ su4 -- mus.
}

LyrB = \lyrics {
  no8 -- stri dam8. -- _ -- _ -- _ -- _ -- _16*5 -- ni8 cau -- sa __ su4 -- 
mus.
}

\score {
  <<
   \new Staff \Not
   \new Lyrics \LyrA
   \new Lyrics \LyrB
  >>
}