Active Directory Properties

Question

Hi guys,
with help I've figured out how to set the "user cannot change password" using the code below. I'm now trying to figure out how to remove the property. I thought setting the denied flag to "allow" would work but it seems to do nothing. I would like the code to be using DirectoryEntry and not PrincipalContext if possible as I'm not sure if my app will be using .NET 3.5 on all the servers. Any help on this would be greatly appreciated.
            string PASSWORD_GUID = "{ab721a53-1e2f-11d0-9819-00aa0040529b}";
            string [] trustees = {"NT AUTHORITY\\SELF", "EVERYONE"};

            ActiveDs.IADsSecurityDescriptor sd = (ActiveDs.IADsSecurityDescriptor)User.Properties["ntSecurityDescriptor"].Value;
            ActiveDs.IADsAccessControlList acl = (ActiveDs.IADsAccessControlList) sd.DiscretionaryAcl;
            ActiveDs.AccessControlEntry ace = new ActiveDs.AccessControlEntry();        


            double denied = (double)ActiveDs.ADS_ACETYPE_ENUM.ADS_ACETYPE_ACCESS_DENIED_OBJECT;
            double objectType = (double)ActiveDs.ADS_FLAGTYPE_ENUM.ADS_FLAG_OBJECT_TYPE_PRESENT;
            double dsControl = (double)ActiveDs.ADS_RIGHTS_ENUM.ADS_RIGHT_DS_CONTROL_ACCESS;

            foreach (string trustee in trustees) {
                ace.Trustee = trustee;
                ace.AceFlags = 0;                
                ace.AceType = Convert.ToInt32(Math.Floor(denied));
                ace.Flags = Convert.ToInt32(Math.Floor(objectType));
                ace.ObjectType = PASSWORD_GUID;
                ace.AccessMask = Convert.ToInt32(Math.Floor(dsControl));

                acl.AddAce(ace);
            }
            sd.DiscretionaryAcl = acl;
            User.Properties["ntSecurityDescriptor"].Value = sd;
            User.CommitChanges();