This method has been tested on different mobiles and has been confirmed to be working.
Followng are the Settings you require to configure on your Mobile:

Account Name: Vodafone_gprs
Homepage: http://live.vodafone.in
User Name: (no need)
Pass: (no need)

Access Point Settings :-
Proxy: Enabled
Proxy Address: 10.10.1.100
Proxy Port: 9401
Data Bearer: Packet Data

Bearer Settings :-
Packet Data Access Point: portalnmms
Network type: IPV4
Authentication: normal
User Name: (no need)
Password: (no need)

*IF that happen this settings is not working then change the proxy portnumber to:-

Proxy Port: 9401