Caching XSModel instead of SchemaGrammar?

Xerces-J has the very useful feature of GrammarPools, caching 
SchemaGrammars (and other Grammars) for use in parsing.  However, in 
recent versions, SchemaGrammar has been marked as an internal class 
subject to removal.  The DOM Level 3 Load and Save XSModel class seems 
to be in some ways similar, but I've seen no way to cache a set of them 
and provide them to a validating parser.  Have I missed something?  Is 
there some documentation somewhere of a way to do this?
Jeff