26. The computer readable medium of claim 1 , wherein said XML entity is a local element declaration of simple type or an element reference referencing a referenced global element of simple type and wherein said wire format specific rendering option specifies that said XML entity is to be rendered for said particular wire format as an XML element and that its value is to be rendered as a value of an additional attribute having a specified attribute name.
1. A computer readable medium for use in validating an eXtensible Markup Language (XML) message in a particular wire format, said computer readable medium containing computer-executable instructions which, when performed by a processor in a computing device, cause the computing device to: from a custom XML schema based message model having at least one wire format specific rendering option associated with an XML entity representing at least a portion of said XML message, generate an XML schema fragment for use in validating said XML message at a node that lacks said custom XML schema based message model, wherein said XML schema fragment conforms to said particular wire format, wherein said custom XML schema based message model comprises a logical model of said message that complies with a standard XML schema, and wherein said custom XML schema based message model comprises a physical model that customizes said message using a logical model extension that is unsupported by said standard XML schema, and wherein said physical model comprises said logical model extension and a wire format specific rendering option, wherein said wire format specific rendering option is a directive that specifies a different wire format for each partial component of said message.