Hi Reinier,
Very good question. I've been working with configuring B2B scenarios the past 2 months, but have not stumbled upon any standard functionality in adapters or adapter modules, which does this kind of validation. I think it's up to the individual developer to ensure that the content of the message adheres to what has been specified in syntax and version.
I would suggest you to add it as a feature request for future version of the B2B components.
I'm just wondering, what would your expected behavior be for handling message content that does not validate against the syntax/version? Should it fail in the adapter/module or should the adapter/module filter away invalid characters? And should you get notified if characters has been filtered away?
Best regards,
Jacob