No, it does not work from internal or external accounts. I've tried all ExternalOOFOptions (including internal) without any of them working.
FYI, when I look at the message tracking log it shows this:
2010-08-31T19:02:37.324Z,192.168.0.3,DC2,,DC2,"MDB:0754ecd6-a74f-44b9-973f-089be36ad410...