There is a _RADIOBUTTON (checked TYPE == 15).
 
Syntax:
Window.AddControl(id, 15, X, Y, WIDTH, HEIGHT,"text label");
Sample:
Window.AddControl(4,15,85,10,80,12,"Second");
Description:
This RADIOBUTTON is checked. A radio button consists of a round button and application-defined text (a label) that indicates a choice the user can make by selecting the button. An application typically uses radio buttons in a group box to permit the user to choose from a set of related, but mutually exclusive options.

X, Y, WIDTH, HEIGHT : - The dialog units. The horizontal base unit is equal to the average width, in pixels, of the characters in the system font; the vertical base unit is equal to the height, in pixels, of the font. Furthermore, each horizontal base unit is equal to 4 horizontal dialog units; each vertical base unit is equal to 8 vertical dialog units.

 
  GUI for script  
Content