Sitemap-based Menu does not get updated correctly when user is on in web.config specified location path

Hi all,
Following scenario:
1) I have a web.sitemap with roles="*"
2) I have a navigation menu with a sitemap datasource
3) In the webconfig i specify some location paths like the following:
<location path="Sections/CANBus/CANBusDetails.aspx">
        <system.web>
            <authorization>
                <allow roles="Systemadmin, Standortadmin, CANBus-Admin"/>
                <deny roles="Working, Reading"/>
            </authorization>
        </system.web>
    </location>
   ...