Ok I solved the problem.
Her is how.
I made a simple html startpage with a start button linking to the KRPano html.
In the xml file I added a back button which links back to the startpage with target set to _self.
Like this
onclick="openURL(../start-aarhus.html,_self)"
When you return to the startpage you get access to the menu and can return to the Good Reader interface.
Hans