apache syslog-ng error logs and access logs

I am trying to send all my apache logs to syslog-ng(on remote machine) which in turn writes to a file.

so I configure syslog-ng this way

source s_apache {
      unix-stream("/var/log/apache_log.socket" max-connections(512) keep-alive(yes));
};
filter f_apache { match("error"); };
destination df_custom { file("/var/log/custom.log"); };
log {
        source(s_apache);
        filter(f_apache);
        destination(df_custom);
};

and add the following line to apache2.conf

ErrorLog "|/usr/bin/logger -t 'apache'  -u /var/log/apache_log.socket"

but only logs being written to “/var/log/custom.log” are

[Mon Jul 13 17:24:36 2009] [notice] caught SIGTERM, shutting down

and

[Mon Jul 13 17:26:11 2009] [notice] Apache/2.2.11 (Ubuntu) configured -- resuming normal operations

I want all logs to be sent to custom.log…..
Please help me…. where am I going wrong?

apache syslog-ng error logs and access logs