I think you asked this before, and I don’t think anyone answered. This might be because a lot of people are celebrating Easter, or it might be because no-one understood the question. In my case, it’s both. Either way, asking it again is unlikely to help.

Schemas are for describing the structure of XML documents. XML documents do not have classes and instances: the only thing that has attributes is an element. You’ll need to explain much more carefully what you are trying to achieve.

Michael Kay

http://www.saxonica.com/