OK, the easiest way is to connect to the maint port on the front of the 3300 using a terminal program 9600,n,8,1
press return until you get an arrow prompt.
Type bootChange
press return until you see "gateway"
enter proper gateway address
press return until you get back to arrow prompt.
The next time you reboot, or system reboots automatically it will use the new settings.
If you enter the address incorrectly, simply repeat the procedure again BEFORE you perform the reboot!