pop login failure not logged to syslog

[steve wright]

Hello,

I've got a few linux systems running cyrus imap 2.1.11 source compiles & a 
few running Henrique de Moraes Holschuh's debian sid packages. I'm use 
sasldb2 (cyrus sasl 2.1.9) for authentication.

I notice when my users supply the wrong password to imapd, messages are 
written to syslog like;
"badlogin: localhost[127.0.0.1] plaintext steve SASL(-13): authentication 
failure: checkpass failed"

When authentication fails with pop3d nothing is written to syslog & i'm 
trying to work out why.

I'm no programmer but I had a look at cyrus-imapd-2.1.11/imap/pop3d.c
Here is what I found;

I noticed lines 1130-1113 read something like, if reply returns true, log 
"badlogin" to syslog.
1130        if (reply) {
1131            syslog(LOG_NOTICE, "badlogin: %s plaintext %s %s",
1132                   popd_clienthost, popd_userid, reply);
1133        }

If I make this read;
1130        if (!(reply)) {
1131            syslog(LOG_NOTICE, "badlogin: %s plaintext %s %s",
1132                   popd_clienthost, popd_userid, reply);
1133        }

Pop login failures are now logged to syslog;
Dec  5 23:47:46 dustpuppy pop3d[4572]: badlogin: [127.0.0.1] plaintext 
steve (null)

I'm guessing (null) means reply was empty / not true?
Why might I be getting this ?
What other information might I supply you to help trackdown my fault?

With Thanks,
Steve.