Well, ANY of the packages installed with fun plug will not show on the Dlink web GUI.
In a few words, you have what is called a "headless server" now with the two services added.
However, most have remote management or tools. For Mediatomb you will have to connect to your NAS as http://ip-or-name:tcp_port, such as http://dns-320:49152. Check you config files for the TCP port you might be using. config file is called config.xml, for more info check
http://mediatomb.cc/For Transmission, Google "transmission remote GUI", similar concept as above.
Tips: start the service before Mediatomb is running. Also can check transmission or any other the same way.
sh /ffp/start/mediatomb.sh start
or check whether it’s already running using:
sh /ffp/start/mediatomb.sh status
Remember, if you want it to start automatically each time the NAS boots you need to set:
chmod a+x /ffp/start/mediatomb.sh
Just keep playing with it, you will get the hand of it. I'm not Linux or Busybox expert but it was not difficult. Do not forget "Google is your friend".