Validating against the correct root element using library schemas

Hi,

I've a question regarding the best practice approach to validating an 
XML document based on a schema which incorporates and OASIS schema library.

If I use a Schema library which has adopted a Salami Slice/Garden of 
Eden pattern, where a number of global elements have been declared, then 
a number of different XML fragments can (in theory) be valid.

My question is how can I ensure that my incoming XML message has the 
correct root element and is not simply a valid fragment?

Do I resort to code to interrogate the incoming message?

Has anyone else experienced this difficulty?

Cheers,

Fraser

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