Repeat midi using "repeat volta"

[Jannik Jeppesen]

Hi,
How is it posible to create a midi file repeating a bar 20 times, but still 
using the command

   \repeat volta 20 {
   }
?

If i write unfold, it generates 20 bars in the layout, and thats not what i 
need.
Until now I have created 2 files, a layout file, and a midi....but isn´t it 
possible to do it in one file?

Best wishes

Jannik