Set unit preferences (Javascript)

I can't find a way to set the unit preferences for Illustrator CS6/CC using JavaScript.

I found that this works (setting units for stroke):

var units = 2; // 0-inches, 1-milllimeters, 2-points

app.preferences.setIntegerPreference("strokeUnits", units)

But I want to set the ruler units ("General" in the interface), and this does not work:

app.preferences.setIntegerPreference("rulerUnits", units)

Any help?

Peter