Hi Raquel,
Are you sure you are updating the server file?
There are 2 locations for the file (config20.xml)
user(s): C:\Users\<UserLogin>\AppData\Roaming\cundus AG\cundusBIPublisher
server: C:\inetpub\wwwroot\SAP BusinessObjects\Disclosure Management\Data\Config
If a user is locally connected, he/she is not updating the server's config20.xml and other users will not see the changes
Marc