There ist still enough memory. You can create your channel list at
http://www.sat-info-page.de/cgi-bin/loader.cgi?settings.
In the combobox at the "Empfänger" line must be set to "D-Box 2 Linux Neutrino ab 26.02."
The next setting which is called "Satellitenauswahl" stands for the satellites you wan't to use.
At "Größe der Schüssel" you set your diameter of your satellite TV dish.
At "Pay-TV Sender" you chose if you want only FTA channels (selecht "Nein") or FTA and Pay-TV channels (select "Ja")
The other settings are unimportant. Now click on the button. At the next page you click at the link near to "Ihre Senderliste zum Download:". Upload these XML files to "/var/tuxbox/config/zapit"
You said you have already a Neutrino D-Box. Therefore you can't make much wrong. Only if you overwrite your Bootloader or lose your ucodes you have a problem. All other things are not so fatal. There is always a way to reactivate your box if you have a working bootloader.
Sorry but i don't know these "Digitall World SCI" therefore I can't help you with these system.
I hope i could help you so far.