If you'd like to have the DUMMY IAP present all the time then all you need to do is install the original Nokia fix:
https://bugs.maemo.org/show_bug.cgi?id=3306

(Basically just apt-get install libicd-network-dummy)

This will permanently install the dummy connection; the usbLAN package is setup so that if you have your dummy network setup this way it will simply leave it alone and forgoe the "auto add/auto remove" functionality for the Dummy connection.

Thanks,
-Rob