Looking for schema management/registry tool

I am currently looking for a tool for a Dutch organization for schema
management in a data exchange context.

I am looking for a tool with the following capabilities:
- storage and maintenance of data definitions and message definitions
- generation of XML Schema and documentation from the above
- version control / configuration & release management of the above
- possibly registry-like capabilities to share the above definitions among
organizations.

Any suggestions for tools to look at?

Thanks, Marc

Marc de Graauw
www.marcdegraauw.com