XML Schema Datatype guidelines

Some time ago we discussed documenting guidelines for using XML Schema Part 
2 with RELAX NG.  What do we need to document?

- The namespace URI to use.
- All builtin datatypes, both primitive and derived are available as type 
names
- Parameters correspond to facets
- whiteSpace facet cannot be used as a parameter
- enumeration facet cannot be used as a parameter (use <value> instead)
- Duplicate parameters: for "pattern" they are anded together, for other 
parameters illegal
- NOTATION effectively works like QName
- ID, IDREF and IDREFS don't have cross-reference semantics (should 
implementations that support DTD compatibility annotations automagically 
turn these into annotations?)

Anything else? Do we want to deprecate things that aren't well-defined?

James