Pb with LDAP and NDS

Hello,
 I try using a NDS server (v7.51) with the LDAP services installed, where a
special user named 'LDAP_Proxy' allow to see other users. 
When I enter in a navigator the following URL:
ldap://x.y.w.z:389/uid=xxxx,ou=Test,o=AA I can see every details about user
xxxx.
 However, with Jahia, when I search '*' or 'xxxx' in the search user list, I
only see the user 'LDAP_Proxy' and cannot see other users !
 I used the following configuration for the file users.ldap.properties: 
------------------------------------------------------
 users.ldap.context.factory = com.sun.jndi.ldap.LdapCtxFactory 
 users.ldap.url = ldap://x.y.w.z:389/
 users.ldap.authentification.mode = simple
 users.ldap.public.bind.dn = ou=test,o=aa
#users.ldap.public.bind.password= 
# the following value will be used as the user key, if it's not found the
user will not be used ! 
users.ldap.uid.search.attribute = uid 
users.ldap.uid.search.name = ou=test,o=aa 
users.ldap.dn.identifier.attribute = cn 
users.ldap.search.countlimit = 100 
# the following defines the attributes to use for wildcard search such as
*=*test* 
users.ldap.search.wildcards.attributes = ou, cn, o, c, mail, uid,
uniqueIdentifier, givenName, sn, dn 
# Map attribute, that indicate which LDAP attribute to map to Jahia standard
properties 
users.ldap.username.attribute.map = uid 
users.ldap.firstname.attribute.map = givenName 
users.ldap.lastname.attribute.map = sn 
users.ldap.email.attribute.map = mail 
users.ldap.organization.attribute.map = ou 
-----------------------------------------------------
 Do you think I have to change the authentification mode (what are the other
enums other than 'simple') or any other parameters ? Thanks by advance, 

Dominique PELLAT