MIDI and transposing instruments

[bernie arai]

i'm trying my hand at finally using the midi output of lilypond to
audition my scores (instead of relying on my horrid piano playing).
after a bit of messing around, and a while looking through the docs,
i'm a bit stumped as to what to try next.  i've defined instruments
for example:

     tenorsax = \transpose c d' \relative c {
% tenor notes (in concert pitch)
}

     tenorsaxone = {
       \set Staff.instrumentName = #"Tenor"
       \set midiInstrument = #"tenor sax"
       \clef treble
       <<
         \tenorsax
       >>
     }

and yet i can't get the midi playback to play the concert pitches,
only the transposed notes (sounds as written).  i'm sure i'm using the
\transpose command wrong, but i don't know how.  any help?

thanks in advance,

bernie