musica ficta, or how to put small accidentals on top of the notes

[Nancho Alvarez]

Some time ago, somebody asked to the list how to transcribe the so 
called "musica ficta".
In the Renaissance era, some of the accidental were not put on the 
score, although they were supposed to be sung.
Modern editors put a small accidental on top of the note.
See a good description in the message 
http://mail.gnu.org/archive/html/lilypond-user/2001-09/msg00026.html

Mats gave us a solution in the message
http://mail.gnu.org/archive/html/lilypond-user/2002-09/msg00161.html
but as it was pointed out, this solution does not transpose nor is 
exported to the MIDI file.
Somebody even suggested a possible syntax.

In the documentation I do not see any reference to "musica ficta", is it 
already implemented? will it be in the future?
I think it is an important feature.

Thank you very much
                                          NANCHO