You can use the "convert function" inside steemworld.org (for all people who aren't able to use programming interfaces).
Converting SBD takes 3.5 days until you get your steem for your SBD.
Nailing (=peg) 1 SBD to 1 USD for every situation in the market is wishful thinking. It will never have success 100%, regardless whatever you do.
I don't believe in fairytales any more.