that method up there will work...
ORRRR a much easier way is
go to Apps->utlities->netinfo manager.
go to security, then authenticate
then
users->select your user-> click the lock
and scroll down, and select where it says HOME and just filling whatever...so if you want it on your firewire, change it to
/Volumes/NAME OF FIREWIRE DRIVE HERE/homedir here
log out
have fun