when you boot the smartxx does it give you an IP in the bottom left corner?
might want to make sure dhcp is on, and each time you leave one of the menus in smartxx leave by choosing save and exit, i've noticed that if you save one screen (such as the bank renaming) and don't save at the next menu, nothing is saved.
also, it's kind of odd to me that you have a defined ip on a crossover cable, are you sure the xbox isn't getting an ip like 192.168.1.10 or something? that would signify a generic internal ip network, and since i'm assuming you're not connected to the internet, due to crossover cable/no router? you don't have a true ip for your xbox.