You can always validate the message from Java code yourself if a Camel component seems not to do what you want.
You may be able to set features to Xerces using Java System Properties or someway like that. You can check the Xerces documentation for that.
AFAIR there is not specific Xerces options avail on the Camel validator component.
But if you show how to enable this feature in Xerces we could consider adding some feature so you can easily set it from the Camel component.