Interacting with Flex in Flash

I was trying to bring a Flex 2 SWF into Flash CS3 and interact with it. I was able to load the Flex swf without a problem but when I tried to access a public property or function I'd get the following error:

ReferenceError: Error #1069: Property hello not found on
_Main_mx_managers_SystemManager and there is no default value.

So I did the natural thing and Googled it before spending time figuring it out :)
Unfortunately, my search came up empty :(

Looking into the docs class mx.managers.SystemManager gave me the clue I needed. To get at the actual application, I needed to get to the first child of the loaded content. The compiler was unhappy with calling getChildAt() on the content object, so I cast it into an Object along the lines:

var flexApp:Object = (loader.content as Object).getChildAt(0);
trace(flexApp.hello);

That did the trick!