autochange Staff

[Guido Amoruso]

Hi,

I'm trying to combine multiple voice in a PianoStaff and I'd like them
to switch automatically the "right" staff (e.g.: all notes lower than
middle c should go on the staff down, while the higher ones on the staff
up).
Is it possible? I'm trying with "\autochange Staff", but perhaps I'm
missing something. Here is a sample of what I'm doing:

************************************************************

VA =
 \notes {
  \time 4/4
   c''4 d'' b' a'
   }
VB =
 \notes {
  \time 4/4
   c'4 d' b a
   }
VC =
 \notes {
  \time 4/4
   c4 f  e d
   }
VD =
 \notes {
  \time 4/4
   g,4 a g f
   }

\score {
\context PianoStaff <
 \context Staff = up < \autochange Staff
  \context Voice \VA
  \context Voice \VB
  >
\context Staff = down < \clef bass
 \context Voice \VC
  \context Voice \VD
  >
 >
}

******************************************************


Thank you in advance.
Guido