Implementing a "logout" sqlcounter

[Ming-Ching Tiew]

I am thinking of using sqlcounter to implement a "logout" counter, 
ie whenever I want to logout a particular user, I set something
into the database, then the sqlcounter will pick it up, and 
drop the existing session.

OK I read in some of the older posts, one way people have 
implemented this feature is via then spin off radclient. 
This has the disadvantage in that, if the radius client is 
behind somekind of firewall, the server initiated radclient 
will have problem sending this to the radius client.

Whereas the radclient continually sending accounting info to
the server, I thought doing the reject at accouting will 
also some what accomplishing the same purpose.

Any comments ?