I just did some tests during the weekend: With Exchange/Outlook the Header works fine. With my own system (Apple Server and Client) the OOf is still coming. Even with Google (Apps).
So: You have to investigate a little bis and figure out which Header might work for your system. Most mailers have a special kind of header that they recognize and respect to suppress the automatic answer.
As soon as you have the right setting, you might test it: Place where i suggested the other setting (Header).
The only other way that i know: Block mails like this on the SMTP Server! I use Postfix with Header_Check and Body_Check Rules to prevent automated answers to all my robots and system accounts.
I don't reject them (That will produce a huge mail loop wave), I just discard them :-)
Ciao
JH