That's a good question. I don't use the autosell feature so I'm not sure. Let me know if you get an answer! One of the reasons I haven't used the autosell is because I assumed that it'd have to wait for the 6 confirmations, so if there was a fire-sale due to falling valuation I could get stuck losing on each transaction.
You'll be stuck anyway, unless I guess you manually sell your own buffer BTC's in an amount equally to what you received in your MtGox with 0 confirms.