When you say "...we configure LDAP like its described in the documentation...", I can assume that you initialized the LDAP Login Module as shown on pg 10, and configured a jBoss user as described on pg 11 of the LDAP Configuration Guide?
If so, have you checked to see if the User you configured is in the Data Protector UserList file on the cell manager
The DpLoginModule login module which is introduced with this feature will be used to authenticate user credentials against the Data Protector UserList and the WebAccess password
The LDAP Configuration Guide has a whole section on Trouble LDAP login and authentication issues
