Metric extension to find db user password change dates

We'd like to report database user accounts that haven't changed their passwords over a particular duration.  The default dataset collected in sysman.mgmt$db_users does not contain that particular information

CREATE OR REPLACE VIEW sysman.mgmt$db_users AS

  SELECT g.host_name,

s.target_name,

s.target_type,

s.target_guid,

s.start_timestamp AS collection_timestamp,

a.username,

a.user_id,

a.default_tablespace,

a.temporary_tablespace,

a.created,

a.profile,

a.expiry_date

 FROM mgmt_targets g,

mgmt_db_users_ecm a,

gc$ecm_gen_snapshot s

 WHERE s.snapshot_guid = a.ecm_snapshot_id

 AND    s.target_guid = g.target_guid