Well, this is the procedure I used when I got a remote for my Z off Ebay; give it a try, I wouldn't be surprised if it's the same procedure you need.
1. Get in the vehicle.
2. Close and lock all doors utilizing the driver's power-door lock/unlock switch.
3. Insert and remove the ignition key more than six times within a 10-second period (at a rate of one insertion/removal cycle per second). Don't rush the process, and be sure the key is completely withdrawn from the ignition-key cylinder each time it's removed.
4. Turn the ignition to the ACC position and press any button on the remote one time. The hazard lights should flash twice, letting you know your mission is a success.