XML schema Management

The problem : managing the production, versioning, consistency, .... of a 
large number of XML schema (typically for message based service interfaces) 
spawned from a core business domain data model.

Scope: Large enterprise integration, internal and external (B2B)

Any one uses products such as igniteXML, corteXML, or the like ...

We are starting to look into this area 9we are swiftly out-growing the 
ability of a small number of talented individuals) and would welcome tooling 
and methodology that other have found to be most useful ?

Regards

Fraser.