Python plugin questions

I am having some difficulty getting my sample plugin working. I'm 
probably making an obvious mistake, but I can't seem to find it. I am 
trying to add a button to the eog toolbar that calls a function when 
clicked. When I run my code and then query for the UI xml from the 
window's ui manager, I see my new toolitem in the XML, but it never 
appears in the toolbar itself. Any help would be appreciated. I am using 
the python console plugin to run the code below.

Thanks,

Steve


import gtk

class MyToolbarItems:

     def test(self, b):
         print "Hello from test"
         return False

     def add_button(self):
         self.uimanager = window.get_ui_manager()
         self.newUi = '<ui><toolbar name="Toolbar"><toolitem 
action="Test"/></toolbar></ui>'
         self.mergeId = self.uimanager.add_ui_from_string(self.newUi)

         print self.mergeId

         self.actionGroup = gtk.ActionGroup("TestGroup")
         self.actionGroup.add_actions([('Test', None, '_Test', None,
                                        'Test this', self.test)])
         self.uimanager.insert_action_group(self.actionGroup, 1)


         self.actionGroup.get_action('Test').set_property('short-label', 
'_Test')
         self.actionGroup.get_action('Test').set_property('visible', True)

         self.uimanager.ensure_update()


     def __init__(self):
         self.add_button()


foo = MyToolbarItems()
print foo.uimanager.get_ui()