expand documentation for the LDAP plugin

docs/manuals/source/TasksAndConcepts/Plugins/FileDaemonPlugins/LDAPPlugin.rst.inc

@@ -8,3 +8,13 @@ This plugin is intended to backup (and restore) the contents of a LDAP server.
 It uses normal LDAP operation for this. The package **bareos-filedaemon-ldap-python-plugin** 
 (:sinceVersion:`15.2.0: LDAP Plugin`) contains an example configuration file,
 that must be adapted to your environment.
+
+Please note that the plugin was tested against an OpenLDAP server. Other LDAP servers
+may behave differently and there might be problems when backing up or restoring objects.
+Most notably, it will not be possible to restore objects to an Active Directory server.
+
+On restore, if the object to be restored already exists on the LDAP server, it will
+be deleted first, then restored from the backup. This could cause problems if your
+LDAP server uses referential integrity (e.g. if a user object is
+restored, the LDAP server might remove the user from all groups when it is
+being deleted and recreated during the restore process).