XML Preloader - XML.getBytesLoaded

I can not build a XML preloader that works.

I am making a project that grabs some information from an XML file. The problem I am having is the document runs before the XML data loads so the text field is blank. If I create a bunch of blank frames before my movie clip needs it, it works fine.

I have tried using XML.getBytesLoaded and XML.getBytesTotal but can not get it to work. Does anybody have an example of how to do this?

Thanks.