Isn't it possible to use the AutomaticUpdater control on a Page like any other control (Button etc.)?
Yes, but only if that page is already sitting on a window in the designer. You can just drag it into it as one of the sub-controls.
In short, the AutomaticUpdater needs to be on a window. You can put it on any of the subcontrols/panels/pages of windows, but it must be on the window.
Does this make sense?