How do I enter triplets programmatically?

Hello all,
I am trying to enter triplets programmatically. This is what the documentation (http://musescore.org/en/plugin-development/tick-length-values) says:

"Note and rest values are expressed in an internal unit (...)
triplet quaver (1/3 of crochet) 160"

So I added this code:
(...)
while (!cursor.eos()) {
var chord = new Chord ();
chord.tickLen = 160;
var note = new Note ();
note.pitch = pitch++;
chord.addNote (note);
cursor.add (chord);
cursor.next();
}

But the result is not what I expected (se attached image). What am I missing, or what am I supposed to do to be able to enter triplets from code?

Thank you,
Claudius