how do I change enharmonic spellings produced by the /transpose function?

[robert edge]

I write music that is not strictly tonal, and years ago I adopted the
convention of always using the same enharmonic spellings.  So my chromatic
scale goes: c cis d ees e f fis g aes a bes b.  I never write something like
an A sharp or a G flat.

Of course Lilypond doesn't know about my silly ideas and \transpose gives me
all sorts of g sharps and d sharps in my tenor sax charts, for instance.

My current workflow is transposing the chart using \transpose, using the
\displayLilyMusic function, pasting the output back in to the source file
and then making the changes using search and replace in EMACS.  

I'd like to automate this process, I've got a lot of charts.  

Anyone have any ideas on how to do this, or where I can find some code that
does something similar I might be able to adapt?

thanks