900Mhz GSM antenna for rfid readers

Anybody tried to use a  High gain GSM 900Mhz antenna for our XR or FX RFID readers ? 

A container terminal customer want to install rfid antennas at about 25 meters high on a Light tower in order to track the container trucks when it passes below it.

We are still looking for a long range  passive tag or battery assisted passive tag to be mounted on the roof of the container truck.  

Tried to ask Intelliflex for BAP tags but they cannot help until next year since they are working on the new RFID-3 BAP tags