hide users from global addresslist via attribute psincludeingab doesn't work

Hi, 

I was looking for a way to hide certain users in the global addresslist, 
and I stumbled upon this ldap attribute (from 
http://docs.sun.com/app/docs/doc/819-4437/6n6jckr1i?a=view) 


psIncludeInGAB 
Origin 

Messaging Server 6 2006Q2; Communications Suite Delegated Administrator 
Syntax 

cis, single-valued 
Object Class 

ipUser 
Definition 

Includes this user in the Global Address Book (GAB) and gives this user 
access to the Global Address Book. 

Allowed values: true, false 

Default value: true 
Example 

psIncludeInGAB: false 


This is exactly what I need, except: it doesn't work 

In the uwc, users with value 'false' are also shown in the corporate 
directory (which I assume is the same as 'global addresslist') ? 
We're using JES6 

Any idea someone ? 

gr, 
Tom