Putting an iframe in a div thats inside a symbol?

I am trying to load an iframe into a div thats inside a symbol. I dont think im getting the path correct?

var externalUrl = "login.html";

sym.getComposition().getStage().getSymbol("Navigation").$("navWrapper").html("<iframe src='"+externalUrl+"' height=230px width=430px scrolling=no frameBorder=0 allowtransparency=true margin=0 padding=0></iframe>");

So the symbol is the ("Navigation") and the div im trying to load a iframe into the div inside that symbol named ("navWrapper")

Dont worry im not loading a navigation through iframe :3

Help much appreciated!