SAP WEBDISPATCHER port 80 is occupied by http.sys

Hi

We are using SAP Portal and there is a confguration with SAP WebDispatcher to use port 80 so that we can access to the URL of our SAP Portal.

With a server restar now the port 80 is in use and it figures out that is the HTTP service of Windows.

However the Windows http.sys is activated and have dependencies to the World Wide Web Publishing Services that are used in our configuration on port 80.

Is there a way of we can use the http.sys port 80 (that is linked to  IIS) with the SAP web dispatcher configuration ?

To use the  SAP Portal  web dispatcher at port 80 does it needs to  stop the http.sys service  and disable this or can it be register the URL of the Sap Portal so that it responds to the http://portal/irj/portal URL ?

Thanks

Sílvia