Hi - there is an example in the pdf file about code caving , I try on the Same game and I got same results but it didn't work with me. Why don't you give a try , may be it will work for ya , I'm not smart at those things
all engines support code caving to become good at code caves learn asm and ppc this makes understanding what you are looking at easier (if you can learn the basics for asm i.e lwz , li, lis, stw , stwz ) then you can pick up how to mod things , then try code caving . I think you would be better starting with a static offset games as you dont need to edit much in them