Internet tethering is now working for me thanks to these settings i found. .
On the device, tap the Settings icon
Choose Wireless & Networks (or Wireless Controls)
Choose Mobile Networks and then Access Point Names
Press the Menu key and then New APN
Select Name, enter: Airtel GPRS and tap OK.
Select APN, enter: airtel-ci-gprs.com
Scroll down to APN TYPE and enter: default or (Select : Internet)
Press the Menu key and select Save
Tap on Airtel GPRS to turn it on
However I'm still unable to use Superbeam!
Phone restarts if i try to send anything through it . .