Combobox list change (javascript) doesn't work in early versions

I´m trying to modify the list of a combobox using the following javascript code:

this.getField('myfield').setItems([["one", "1"],["two", "2"]]);

The code works as expected in recent versions of acrobat readers (15 or 20), but does nothing in older ones such as 8 (app.viewerVersion). This 8 version is the one installed by default inside Edge web browser at the company I work.

I also tyied to modify the list by erasing and adding entries but the result was the same: no errors but nothing changed.

Is there any known workaround to make it work in every environment?

Thanks in advance.

Sebastian Lorenzo