Sending UDP data using GSM shield

Hi guys,
I am trying to send UDP packets instead of the default TCP packets. So i modified the library files accordingly. I changed the TCP to UDP in the 'GSM3ShieldV1ClientProvider.cpp'. So by doing that the code sends the AT commands that sets the transport layer to UDP. But the problem is that after doing these changes, I tried the TestGPRS sketch and there is no response generated when the modem tries to connect. Any ideas on how to implement ?

Also any idea about using the AT Command Tester ? It is an online tester for testing AT commands on a modem. It is told to work with arduino. But When i try connecting it is is telling no response. Any help would be appreciated !!!
link : http://m2msupport.net/m2msupport/module-tester/

Thanks in advance !!