Robert,
Ok. I finally got it. The import statements for the 1.3 API are:
import com.esri.solutions.flexviewer.AppEvent;
import com.esri.solutions.flexviewer.SiteContainer;
So I added those to the MXML of the widget that contains the button to launch the identify tool, and the MXML for the button is:
<mx:Button id="idButton" label="Identify Features" click="SiteContainer.dispatchEvent(new AppEvent(AppEvent.WIDGET_MENU_CLICKED, false, false, 5))"/>
Thanks again and I appreciate your patience with someone new to Flex.
Bill