gxangel,

You will need to set the audit_trail to DB_EXTENDED and to restart the instance because the AUDIT_TRAIL parameter it is not a dynamic parameter.

Look this:

AUDIT_TRAIL.
This has four possible values:
• NONE (or FALSE) Database auditing is disabled, no matter what auditing
you attempt to configure.
• OS Audit records will be written to the operating system’s audit trail: the
Application Log on Windows, or the AUDIT_FILE_DEST directory on Unix.
• DB (or TRUE) The audit records are written to a data dictionary table,
SYS.AUD$. There are views that let you see the contents of this table.
• DB_EXTENDED As DB, but including information on the SQL statements
with bind variables that generated the audit records.


I hope I have helped you.