Adding node to XMLList object

I have the following ‘myXML’ XML object:

<layout>
<region id="main" left="295" width="458" top="35" height="343"/> 
<region id="subs" left="265" width="520" top="440" height="50" />
<region id="links" left="45" width="150" top="70" height="180" />
<region id="video" left="48" width="160" top="330" height="125" />
<region id="links-down" left="45" width="150" top="165" height="95"/>
<region id="links-small" left="45" width="150" top="60" height="100"/>
</layout>

and ‘’ nodes loaded inside a XMLList object called ‘xml_list’:

 var xml_list:XMLList = new XMLList(myXML.region);

and i would like to add for example this node to that XMLList:

 <region id="test" left="0" width="0" top="0" height="0"/>

How can i accomplish that? :ponder:

thanks in advance,
best regards