Specify Size of Image via ExportOptionsPNG24 ?

Hi!
In documentation (ADOBE ILLUSTRATOR CS4 SCRIPTING REFERENCE: JAVASCRIPT)
the ExportOptionsPNG24 does not have any property for
width/size/dpi/pixel (just scale).

Is there a way (like in the "Save For Web" dialog) to specify the size of the exported PNG in pixel or filesize?

var options = new ExportOptionsPNG24();
options.antiAliasing = true;
options.transparency = false;
options.artBoardClipping = false;
var file = new File(folder+"/"+layer.name+".png");
document.exportFile(file,ExportType.PNG24,options);

Or does the script take the values from last manual PNG export?