Hi Charles,
If you assign something that isn't a number to a numeric field, it shows you a zero. The rawValue from a drop down is a string, so you need to cast it to a number. Try using the JavaScript ParseInt function. The second parameter is the radix (base 10). Something like:
var strNumberishString = xfa.event.newText;
var nIntegerThing = parseInt(strNumberishString,10);
oNumericField.rawValue = nIntegerThing;
I hope that works for you.
Jared Langdon
J. Langdon Consulting
www.jlangdon.ca