Squid 1.2beta18 and SNMP

I'm trying to use with MRTG and Squid.
But squid did not respond to SNMP request.

$ snmpwalk -v 1 133.210.2.24 public -p 161
No Response from 133.210.2.24
(133.210.2.24 is my proxy server)

I configured with --enable-snmp(BSD/OS 3.0).
cachemgr.cgi works well.
And, my configuration is this.

snmp_port 161
snmp_trap_community public
snmp_enable_authen_traps off
snmp_agent_conf user squid - all all public
snmp_agent_conf user all all all all squid
snmp_agent_conf community public squid squid
snmp_agent_conf community readwrite all all

How to configure and test for SNMP?

--
       $B8~@n(B $B?.0l(B <Mukaigawa Shin'ichi>
       mailto:shin@ari.ncl.omron.co.jp
       http://www.wg.omron.co.jp/~shin/