import mx.managers.ToolTipManager;
import mx.controls.ToolTip;
import mx.events.ToolTipEvent;
public function initApp():void {
b1.addEventListener(ToolTipEvent.TOOL_TIP_SHOW, myToolTipChanger)
}
public function myToolTipChanger(event:ToolTipEvent):void {
ToolTipManager.currentToolTip.text = "Click the button, " + Application.application.parameters.myName;
}