是否有关于IDML HTMLItem规范和HTMLItem海报属性的文档？

I'm working with coding with the IDML documents and I'm looking for more information on the IDML HTMLItem. I have both the version 7 and version 8 of the IDML specification and have not found anymore information then a small mention in the "new elements" of version 8, I'm working with coding with the IDML documents