Sequence diagrams: notation in chapter 9 (Howard Sheil)

Dear forum users,

This is a question for everyone who already passed the SCEA exam and based their assignment on the example that was given in the famous chapter 9 from Howard Sheil's book. I would like to know if you used the same kind of arrows as well. For me, it's a bit strange that author uses asynchronous arrows (->) all the time (in both directions) It's not really obvious to me to see the distinction between synchronous and real asynchronous (e.g. the message to the mail server) messages that way, and - IMHO - this is an important aspect in the sequence diagrams.

Thank you very much for your answers.

Lot's of other issues as well:
http://www.coderanch.com/how-to/java/CadeSheilSceaFaq

I'm doing part 2 also and I am NOT going to "copy-paste" UML notation errors to my diagrams.

Thank you for your reply, Jari. Good luck with part 2!

Carl,
I added yours to the wiki page. And I most certainly did not use async arrows for synchronous calls in my submission!

Thanks for your reply, Jeanne. Something tells me to make some changes in my diagrams