imap logging problem

[Alejandro Osorio <aosorio fi uaemex mx>]

Hi all,

Everytime a user reads mail from the server, three lines appear in 
/var/log/maillog, like this:

Aug  9 09:22:16 xxx ipop3d[1344]: pop3s SSL service init from a.b.c.d
Aug  9 09:22:21 xxx ipop3d[1344]: Login user=<username> host=[a.b.c.d] 
nmsgs=0/0
Aug  9 09:22:21 xxx ipop3d[1344]: Logout user=<username> host=[a.b.c.d] 
nmsgs=0 ndele=0

But, in some rare cases, the two last lines are delivered to 
/var/log/messages instead of maillog.

How to fix this?

(I'm using rh 7.3, imap-2001a-10, sysklogd-1.4.1-8)

Thanks in advance.