Active Directory 2008 R2: Enforce Password History Does not work on domain users

Hello All,

We have a DC windows 2008 R2 and have tried below to enforce password history.

1> 'Enforced' Defualt domain policy which has 'Enforce Password History' as '24 Password remembered'

2> Created a  new password policy with 'Enforce Password History' as '24 Password remembered'

3> Tried fine grained password policy as shown here http://blogs.technet.com/b/seanearp/archive/2007/10/06/windows-server-2008-fine-grained-password-policy-walkthrough.aspx

But no luck at all. I am still able to reset a domain user's password to old one using 'Active Directory Users and Computers'. I am doing it as domain administrator.

I also tried the hotfix mentioned here http://hotfixv4.microsoft.com/Windows%207/WindowsServer%202008%20R2/sp1/Fix314655/7600/free/419101_intl_x64_zip.exe

Is there something I am missing? Please help. Thanks.

/M