Faisal,
I am assuming that you have some sort of radius server for billing/accounting, so you will need to setup the LCRGs for the phones, and the radius userserver for the radius. You will also need to setup either static route(s) to the destination IP address(es) or the h323gw area if you plan to have the Tenor registering to an external gatekeeper.
If you require more detailed configuration, please contact me at mike_voip@hotmail.com and we can further discuss.
Mike