Apache 2, mod_ldap, mod_auth_ldap, SSL

Hi,
I have following problem. I have an Apache httpd v2 running. One of it's URLs is secured by an LDAP authentication encrypted via SSL. This works fine with the given directives. Currently there is following directive to tell with which LDAP server to authenticate:

AuthLDAPURL "ldaps://10.1.2.3/ou=users,o=company,c=com"

All is fine as long as I use IP-addresses. When changing this to a hostname in short form or as FQDN or even an alias from DNS (that can be all reached without problems, then I get the following in the log the modules produce for SSL:

[Thu Aug 19 15:38:29 2010] [warn] [client 10.8.4.24] [323614] auth_ldap authenticate: user someuser authentication failed;
 URI /somedir [LDAP: ldap_simple_bind_s() failed][Can't contact LDAP server]

When I change ldaps to ldap so that SSL is not used, I can use IPs and names in any way I want. Adding port 636 explicitly when trying names with ldaps does not make a difference.
I checked all directives from mod_ldap and mod_auth_ldap but couldn't find any that might relate to this.
Also I am not sure if the certificate I got from our CA has some information in it like, that might relate to this problem (I doubt that).

I googled also a lot and found similar things but often without usage of SSL and only 1 thread in some mailing list where the guy solved it but didn't describe it in detail.

So any hint is very welcome, thanks.

Cheers
zaxxon