lock active office accounts programmatically

i have close user accounts active office programmatically c#.

unfortunately doesn't work around useraccountcontrol attribute. each i set useraccountcontrol 528 (=normal comment w/ lockout flag), active office won't accept value resets but offer notice 512 (=normal account).

now i attempted close comment providing crude certification (see below), nonetheless doesn't work either.

int retries = 0;
while (!adsuser.isaccountlocked && retries < max_lock_retries)
{
     retries++;

    try
    {  
        new directoryentry(userpath, logonname, incorrectpassword).refreshcache();
    }
    locate (exception)
    { 
        /* ... */ 
    }
    adsuser.getinfo();
}

any ideas?