magic orb, in case you did not get your question above answered, and for anyone else with the same question....
In the list of editing boxes above the post content box, go to the last box, next to the box that resembles an I Ching hexagram (labeled "Insert Horizontal Line"). This last box looks blank, has no symbols on it, but if you hover your mouse over it, you'll see two boxes labeled (1) "Wrap
Actually, I don't even know what #2, an tag is, let's find out.... Ah, it's a cross-through, was wondering where that was!
The Mysterious S tag!