you peg your listings to the USD value of BTC in your account settings. You still have to write in the value but when you do your listing just divide the USD price you want by how much it's worth in BTC (i.e. if you want something to sell foe $25 you currently would divide it by 13.64, so your llisting would be at 1.83 BTC.Also that is where you enable escrow - there is a breakdown of how it works in the seller's guide.