LdapContext getResponseControls() always return null?

We use Sun One Directory Server 5.2 and have configured user password policy to expire 10 days from reset. Now I have a user whose password is about to expire and "passwordExpWarned" attribute is set to 1 by Directory Server already.

However, when my Java code trying to read the LDAP Controls back, getResponseControls() always returns null. The source code follows the example from

http://archives.java.sun.com/cgi-bin/wa?A2=ind0101&L=jndi-interest&P=R5 327

Do I need to change any configuration on Sun DS server to activate the LDAP Controls for PasswordExpiringResponseControl (OID = "2.16.840.1.113730.3.4.5")?

When I check on AdminConsole, my server under "cn=features,cn=config" only shows "2.16.840.1.113730.3.4.3" which is persistent search, but no password control OIDs, is that the reason that I do not receive response controls back?

Thanks,

[900 byte] By [jz_mavericka] at [2007-11-27 2:39:17]