Follow the destructions for replacing your HD. After you start up your system, connect to the Serial port (Null modem, 9600/n/8/1) and log in. Follow the platform initialization menu and run Universal Profile. It will take about 45 minutes to complete and perform several reboots. When complete (LEDs cease flashing), log in on the default IP addres/username/password and make the necessary programming changes (IP, User accounts) and re-enter your keycodes manually.
You then rebuild the VM system as it was. If you have all the prompts backed up as .wav files, you can have a full AA and CCR tree setup rebuilt in about 20 minutes tops.
IMHO it's not as painful as it sounds. I've done several upgrades from 2.5 and 3.01 to 3.7 this way and it's far faster and less prone to failure than the normal upgrade path.
HTH.