Did you, on the server, change the new, undocumented, /etc/sysconfig/ldap file's entry for SLAPD_LDAPS and restart the ldap service on the server?
This settings was indeed set to no.
What is funny though is that I actually can connect to the ldaps port without it (since ldapsearch -x is working and I can also connect via ldaps using a graphical client, and the plain ldap port is closed by the firewall)
I changed the settings to yes and restarted the service, but it did not change anything.