Windows Home Server provides you with your own custom domain , so you don't need it via Dyndns.
What he is actually asking is how to configure the Mega100WR correctly so that the custom Homepage displays correctly allowing him to log onto his WHS from a remote location , without encountering the Mega100WR logon screen.
In the settings for setting up your "WHS webpage access" it attempts to configure the UpnP, Port Forwarding for the router, but fails to complete.
Therefore he requires someone that is familiar with this to provide him with a step by step process fo how to configure it in the Mega100WR webpage gui, I have tried, but failed and just given up for now.
Also the step by step portfowarding on portfoward doesn't really make it work either, tried that also.