You should know RPC/Literal and RPC/Document encoding. You should also understand RPC/Encoded. People are moving away from RPC/Encoded because its not very interoperable, but J2EE 1.4 still supports it so you should understand the basics.
Thanks Richard I was just making my point because when I looked at this post I was currently reading page 107 of your book that exposes the different SOAP messaging modes I really much like your book by the way. Thanks for providing such a great resource