I'm using the same version of mail as you are - fresh MacBook system, no other mail programs or handlers installed - if you can point me to what configuration information OF is looking at to grab that, I can check it.
(and I should have put the 2nd paragraph of my original note in a separate post - but I see someone just made a post on the same topic:
http://forums.omnigroup.com/showthread.php?t=5646)