OpenLDAP slapd replication

[Jorge Ruão <jruao@fe.up.pt>]

Hi,

I've set a OpenLDAP server runing slapd daemon in a Slackware 9.1 
distribution.
My salpd.conf has the following line:
______________________________________________________
replogfile      /etc/openldap/master-slapd.replog

replica host=apollo.fe.up.pt:636 tls=yes
       binddn="uid=updatedn,ou=admins,dc=fe,dc=up,dc=pt"
       bindmethod=simple credentials=secret
______________________________________________________

My question is that when i start slapd, and after adding a new entry and 
some changes, the files:
-master-slapd.replog
-master-slapd.replog.lock
where created but both are a zero length file. No changes are introduced 
in those files so that slurpd can handle them to the replicate to the 
ldap slave host.

Any reason why slapd.replog file is not being populated with changes 
introduced in the server?

My thanks,
Jorge Ruão