auid field when switching user

Bonjour, I'm trying to use auditd to log all actions made by the users on the system. This part works fine. The documentation mention the "auid" field to identify the user from the first connection "even" when the user's identity changes (like with a su): auid=500 The auid field records the Audit user ID, that is the loginuid. This ID is assigned to a user upon login and is inherited by every process even when the user's identity changes (for example, by switching user accounts with the su - john command). But this is not working. If I log with the user "test" (uid 1000) when I switch to the user root, the value of auid is 0 (the uid of root). Did I missing something ? Thank you in advance. Regards, -- Guillaume