Naming midi files

[Mark Probert]

Hi.

If I have a book that is structured something like below, then LP 
produces two midi files: foo.midi and foo-1.midi. 

Is there a way I can coerce the names into "bar.midi" and "baz.midi" 
within LP? Or is this something best down externally?

Thanks again

 ..mark.

-- foo.ly
\include "bar.ily"
\include "baz.ily"
--
-- bar.ily
\bookpart {
  \header {
    title = "Bar One"
  }
  \score {
    % music
    \layout{}
    \midi{}
  }
}
--
-- baz.ily
\bookpart {
  \header {
    title = "BaZ"
  }
  \score {
    % music
    \layout{}
    \midi{}
  }
}
--