If I read your question correctly, you plan to bid early in the auction without using AS, and then use AS to snipe at the end. AS is not governed by what you do outside its sphere, that is, nothing from your earlier bid will carry over into your AS snipe bid. Set it up as though you had never bid. If you use the same eBay userid both times it won't matter that you bid against yourself. eBay will treat that as two bids by the same person and you'll only be liable for the minimum amount needed to win the auction (assuming your snipe is high enough to win).
The same is true if you use AS for both bids, setting each one up as a separate bid. But
I'm curious to know why you would want to "tip your hand" by bidding early in the auction, unless it's to prevent someone else from using the "Buy It Now" feature. The whole idea behind sniping is that your opposing bidders never see you coming. Most of the time that gives them a false sense of security and will keep the final bid lower.
