Radio button isn't checked after "click" event

I do have a form with two seperate subforms. There are also two radio buttons (called "int" and "ext") at the master page. The radio buttons are grouped into an option field.

There is an script in the radio buttons which controls the presence of the two subforms. If radio button "int" is clicked subform "Tform1_int" has to be visible, if radio button "ext" is clicked "Thorm1_ext" has to be visible.

The scripts works as it should but every time a radio button is clicked and the script runs the radio button isn't checked afterwards. And of course the radio button has to be checked so the user knows which subform is shown.

The script for the radio button option list "click" event:

if (this.rawValue == "int"){
	this.resolveNode("App.Tform1_int").presence = "visible";
	this.resolveNode("App.Tform2_ext").presence = "hidden";	
}
else if (this.rawValue == "ext"){
	this.resolveNode("App.Tform1_int").presence = "hidden;
	this.resolveNode("App.Tform2_ext").presence = "visible";
}