Hi,
If I see you well, then you would like to change the default web server port (80) on your NAS to another one (ex 8080). If yes, then please read my post (
http://forums.dlink.com/index.php?topic=57212.0)
You don't need to do everything, just install the fun_plug, then do the rest until the "Now you are ready to make your NAS as a real home server ... " step.
The Copy lighthttpd.conf and mimetypes files from /etc/lighttpd to /ffp/etc/ directory
Edit the file. Find the row: server.port = 80, and change the port number to any, which would be good for you.
After that you have to restart your lighttpd with the following lines
Start the lighttpd service, and make it as autorun, as you can read in the forum above.
I hope it helps you