Flex - Updating An IFrame Without A Page Refresh Using Actionscript 3?

I would like to have a FLEX SWF Menu in .NET that is animated, and use button clicks to update an iFrame in an .NET 2.0 Ajax enabled application without a page update or refresh. If I use URLVaribles in Flex, The only way I've gotten to them to ASP.NET is via URL Page Navigation which always refreshes the screen. There is a LOADVARS function but I have not gotten it to work. Is there any suggestion on how one would do this??

Do I need to look into using JSON for Flex??? Or WebOrb???

This works fine... but with a page refresh (which is not cool)...

navigateToURL( new URLRequest( "http://localhost:50294/WEBAPP/Default.aspx?P=2&H=500" ), "_self" );

This does NOT work fine... (in fact it just loads the whole page .NET page in FLEX, not what I am looking for)

var variables:URLVariables = new URLVariables();
variables.P="1";
variables.H="400";
var request:URLRequest = new URLRequest();
request.url = "http://localhost:50294/Timber2/Default.aspx?";
request.method = URLRequestMethod.POST;
request.data = variables;
var loader:URLLoader = new URLLoader();
loader.dataFormat = URLLoaderDataFormat.TEXT;
loader.addEventListener(Event.COMPLETE, uploadComplete);
try
{
loader.load(request);
}
catch (error:Error)
{
trace("Unable to load URL");
}