\transpose and quoted music

[Jérôme Plût]

Let's say I am typesetting some orchestra music written for a horn in
D and want to output it for some other, more reasonably-pitched
instrument.

I entered the music in this way:

global = { \key d \minor }
cues = \relative { c'4^"Cue" c c c } \addQuote "cues" \cues
hornA = \transpose c d, \relative {
  \cueDuring #"cues" #UP s1 c'4 c c c }
% Both \cues and \hornA are consistently in concert pitch, which
% is the most idiot-proof way of entering music. The \transpose command
% is here to help entering the notes from the original source in D.

\score { \transpose c' f << \global \hornA >> }
% I can also produce a score in concert pitch for the case where the
% horn is replaced by a trombone in an emergency...

Since \transpose has this strange behaviour that it does not touch
quoted music (... but why?), the resulting PDF has the horn notes in
F, but the cues are still in concert pitch, which is less than fully
helpful to the poor horn player.

I tried some various combinations to have cues in F, such as those
below, but to no effect at all :

% this would be preferable, because it is locality-preserving
\transpose c' f << \transposition c' \global \hornA >>
% uglier (need to specify the “f” pitch twice) but would still be workable
{ \transposition f \transpose c' f << \global \hornA >> }

I know one sure-proof way to solve this (by writing a custom
\sanetranspose Scheme function that goes deep in the music and
replaces all the \cueDuring by \transposedCueDuring etc.), but this is
surely not the most elegant way. Is there a simple way to make
\transpose behave reasonably?

Thanks,

-- 
        Jérôme