adding subscript to XML pulling data via E4X

CS4 and Player 10 have additional package for this kind of things:

flash.text.engine

Otherwise, as for subscript, you can accomplish it with StyleSheet (see code below) - this is not an ideal subscript but some can bare it. As for the superscript or more adequate subscript, things are getting hairier. There are some solution on Internet - search Google. In a nutshell, there are AS3 packages that do that, or one can create such an engine himself or use special fonts that are also available.

var styleSheet:StyleSheet = new StyleSheet();
               
var styleObject:Object = {
     fontFamily: "Arial",
     fontSize: 12
}
styleSheet.setStyle("p", styleObject);
               
styleObject.display = "inline";
styleObject.fontSize = 8;
               
styleSheet.setStyle("sub", styleObject);
               
var textField:TextField = new TextField();
textField.styleSheet = styleSheet;
textField.autoSize = TextFieldAutoSize.LEFT;
               
textField.htmlText = "<p>example with G<sub>subscript</sub> text.";
               
addChild(textField);