terminate session

Hi All, I am using the latest freeradius and coovachilli and am having a terminate session problem. Some user sessions are not stopping, the session time shown in the DB stops but the user does not logout and there is also no reason given in the DB for termination... The user can also go over the ChilliSpot-Max-Total-Octets quota and the Idle-Timeout does not appear to work. How does radius send a stop session command to the coovachilli router, perhaps that's where the issues is? Regards Carl