Book Designer converts emdashes (—) and -- to just a single dash. What I have been doing is converting emdashes and -- to @@. Then once inside book designer, I can convert @@ to — (emdash) correctly.
One other note, becuase of the poor italic handling by the Sony Reader, if there are any symbols or 's type things right after the italics, I italicize them too. Otherwise, you get something like Bob 's house. My way you do get Bob's House. Granted there is a little bit of extra space right after an italic. I hope Sony will eventually fix this.
But overall, I do like the tutorial document. I think it is a great idea.