IconDialog customLocation

[chiasa.men]

My plasmoid provides icons. I want to use an IconPicker so that the user can
decide which icon to use. Therefore Im using the following snippet:
import org.kde.kquickcontrolsaddons 2.0 as KQuickAddons
...
    KQuickAddons.IconDialog {
        id: iconDialog
        onIconNameChanged: {
            iconPreview.source = iconName
            iconChanged(iconName)
        }
        customLocation:'/absolute/path/to/images/'
    }

Which works, but only if the user clicks manually within the IconDialog on
"Other Icons:" radio button. By default "System Icons:" radio button is
checked.

How can I change the default setting in order to present the user
automatically the delivered icons?