Refresh lookup method


I’m new to ScriptCase and I am facing the following problem.

I have a form with three Select fields: Country, Region and Subregion. They behave in cascade, so I show every country, then the regions belonging to the selected country and the subregions belonging to the selected region. All three fields are based on variables.

I’m trying to populate the fields in the Onload event, but I can’t refresh the edition lookup, ie: the Select is not aware of the modifications I’m doing on the fields.

Any hint about how to solve this problem?