Facetime does not work on Jailbreak 4g 4.1 on Airtel Network in India

Hello,

I have a jailbreak iPhone 4g with OS 4.1 on it. I reside in India and my Telecom service provider is Airtel. I tried to activate Facetime on my iPhone but I keep on getting the error message 'Waiting for activation'. I tried all the options available on various forums on the internet but could not succeed. However my friend who has a iPhone 4g Factory Unlock piece, on it facetime works fine on Airtel connection. I also have International dialing, MMS, SMS activated on my mobile connection and these services work fine.

Regards,
Dharnidhar