How to enable only EAP-TTLS type and not EAP-TLS?

Hi, I want to enable only TTLS authentication and if the client is requesting any other types EAP-TLS or PEAP the authentication should be denied. I am running freeradius-1.1.6, and if try to disable EAP-TLS module the server itself is not starting up. Please let me know if there are any ways to achieve this. Thanks a lot.. Nikitha.