[Oracle DB 11gR2] Auditing dropped indexes

Hello,

I am trying to figure out how to "audit" the schema structure modifications and more precisely, the drop index action.

Here is my current setup:

sho parameter audit

=>

audit_file_dest	string	/oradata/oraaa001/admin/adump
audit_syslog_level	string
audit_sys_operations	boolean	FALSE
audit_trail	string	DB

=> I have tried these:

AUDIT DROP ANY INDEX;

AUDIT DROP ANY INDEX by test_audit;

=> confirmed by:

select * from sys.dba_priv_audit_opts where privilege like 'DROP%INDEX%';

USER_NA PROXY PRIVILEGE

SUCCESS

FAILURE

------- ----- ------------------------- ---------- ----------

	DROP ANY INDEX	BY ACCESS  BY ACCESS
TEST_AU