Change LDAP authentication from AD to ApacheDS

CentOS 7
Nginix with php-fpm
owncloud 8.2

Hallo everybody,

we did setup owncloud with ldap-Authtication using our internal AD. This works
perfectly.

Now we want to move some external users from our internal AD to an ApacheDS.

Does anybody have any experience how to handle a scenario like this? Our idea was
that we have to the change the content of the field 'ldap_dn' in the table 'oc_ldap_user_mapping'
of the owncloud database so that it matches to the dn of the ApacheDS.

After moving the external users to the ApacheDS the next step is to configure openID
authentication.

In the past there was an external App to handel this but the app is not available
anymore. Does anybody know a workable way to do this? Is there an alternative
installing OpenID in Owncloud?

Thanks in advance
Ivo