DOCBOOK: Customization and classes

Hello,

I'm trying to write a customization layer and have identified the 14
elements I need to add to the info pool, but am having a hard time figuring
out what they are similar to, and which class things are in, in order to add
the right class info. Your book and online guide provide one customization
example that takes an element and duplicates its attributes and class
entities exactly, but it's the only example I can find. Can you provide any
more customization examples than your book or online guide does?

Thanks,
Lisa