iframe on a symbol created dynamically

Hello,

-I have a button that creates a symbol dynamically. That is OK

-then I move this symbol with TweenMax. That is Ok, I tested it.

-and finally I want to load into this symbol  an external URL. That doesn't work.

The problem is, I think, I don"t know how to address this dynamically created symbol.

This is my code :

var externalURL ="portfolio/FFD.html";

var mywrapper = $(sym.createChildSymbol("wrapper","Stage").getSymbolElement());

var wrapperMove = TweenMax.to(mywrapper,2, {css:{top:"2500", left:"0"},ease:Sine.easeOut} );

sym.$("mywrapper").html("<iframe src="+externalURL+" height=100% width=100%></iframe>");

Thanks for any help