Well, first this is a message board. The obama campaign isn't going to do this, and the american public isn't reading this obscure board.
Second, the way to do this, is just how the republicans have done it for years. Make it a whisper campaign, and spread viral emails through the internet. It can't be traced to Obama.
Where do you think the Reverend Wright "fiasco" started? With republican whisper campaigns, and republicans passing racist emails to each other and spreading the viral messages on the interwebs.