Lilypond's English Horn MIDI instrument is non-transposing?

[James B. Wilkinson]

I'm working on an arrangement fordable-reed quartet. Here's the score block:

\score
{
  \new StaffGroup
   <<
     \new Staff = "oboe1" \with { instrumentName = "oboe1" midiInstrument = 
"oboe" }
       { \clef "treble" \soprano }
     \new Staff = "oboe2" \with { instrumentName = "oboe2" midiInstrument = 
"oboe" }
       { \clef "treble" \alto }
     \new Staff = "EngHrn" \with { instrumentName = "enghrn" midiInstrument = 
"english horn" }   %"english horn"
       { \clef "treble" \transpose f c \tenor }       %the correct 
transposition for EH sounds terrible
%       { \clef "treble" \transpose c c, \tenor }      % temporarily down one 
octave; sounds fine
     \new Staff = "bassoon" \with { instrumentName = "bassoon" midiInstrument = 
"bassoon" }
       { \clef "bass" \bass }
   >>
  \layout { \context { \Staff \consists "Ambitus_engraver" } }  
  \midi {  \tempo 4 = 80   }
}


If I make it with the English horn part correctly transposed, the MIDI sounds 
terrible. If I make it with the English horn part untransposed, it sounds fine. 
My conclusion is that the midiInstrument "english horn" reads its part in C 
rather than in F. Shouldn't it play the notes that a real English horn would?


thanks