Adding Lines to a XML file

Alright im trying to figure out how to take the xml gallery tutorial, and add the ability to add lines to the xml from the swf itself.

The swf would just be 2 text boxes, one having the url to the image, and one for the caption


<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<images>
    <pic>
 <image>http://www.phirebrush.com/issues/38/photography/54ka%20-%20Treestory.jpg</image>
        <caption>PHIREBRUSH!!!!</caption>
    </pic>
    <pic>
 <image>*USER DATA*</image>
       <caption>*USER DATA*</caption>
    </pic>
</images>

Make sense? can anyone help?