[flexcoders] createPopUp question

[markgoldin_2000]

Sorry have to ask that again.
How can I make this function working:
public function showPopupWindow(parent:DisplayObject, 
WhatToShow:String):void
{
 var helpWindow:TitleWindow =
 TitleWindow(PopUpManager.createPopUp(parent, WhatToShow, true));
 PopUpManager.centerPopUp(helpWindow);
}       
createPopUp does not take WhatToShow as a parameter.

Thanks for help.