sshd idle session

[atstake atstake]

I am using ssh (OpenSSH_4.4, OpenSSL 0.9.7j) on OpenBSD4.0. I want
idle user sessions to timeout after a certain period. I tried
ClientAliveInterval 15 and ClientAliveCountMax 3 in
/etc/ssh/sshd_config & restarted sshd which, according to
sshd_config(5) should end the idle user session in 45 seconds. Anyhow,
that's not working and I was wondering
if there's any other way to end/timeout idle users' ssh session. My
shell is bash.

I don't want to use idled or TCPKeepAlive if I can help it.

Thanks.