I have done this, although it is not technically part of the toolbar, it looks like it.
Added the widget to the UI elements (along with the full screen widget) so it is there when it opens and works with one click.
code:
<widget right="150" top="5" config="widgets/FullScreenWidget/FullScreenWidget.xml" url="widgets/FullScreenWidget/FullScreenWidget.swf"/>
<widget right="109" top="5" config="widgets/ExportMap/exportMap.xml" url="widgets/ExportMap/exportMap.swf"/>
see attached image.
<!-- UI elements -->like the NavigationWidget
Jeff,
Updated version 2.2 is now in the code gallery.