How to change router admin to a different port ?


I have dynamic IP address from Airtel and using Beetel 110 BX router/modem.
Whenever I visit my hostname from inside the LAN or outside
I am taken to the router settings page.
I have set apache to listen to port 80.

But the routers settings is also in port 80 ie

When I do port forwarding for port 80 the router settings page says that the
DSL router server will be changed to 8080 but it does not happen.

So how do I change the router settings page to a different port say 8080 ?