Here's what we need to do:
apt-get install sg3-utils
/usr/bin/sg_raw /dev/sr0 11 06 20 00 00 00 00 00 01 00
/etc/network/interfaces and add the following:
iface eth1 inet static address 126.96.36.199 netmask 255.255.255.0 gateway 192.168.1.1
Then restart the network
/etc/init.d/networking restart and now you should be able to reach the Huawei web server on http://192.168.1.1 as well as the internet.
Note: You may have to set the E3131 network controller mode again if you reboot the Raspberry Pi, although the 2nd time I rebooted it, I noticed the setting was already in network controller mode.