Translation of hisway's post: Faith ain't enough - you've got to perform a work in order to be saved.
You comparison of the old covenant sign of circumcision to the new covenant sign of baptism is all fine and dandy. Just one thing, though...... the old covenant was an old covenant, and the new covenant is a new covenant. You can't just unilaterally say that everything that was applicable for the old is automatically applicable for the new.
You can try to defend this position all you want, but the simple fact of the matter is that there are way too many verses and passages that say that salvation is a gift of God by faith alone, not of works (of any kind), for this "you-must-be-baptized-in-order-to-be-saved" doctrine to hold any water.