I can't believe this is a legal schema, but apparently it is... Sigh.
I can tell you that this won't work in the current version of JAXB RI.
The workaround could be to write an XMLFilter that fills in a correct
default value as if it's there in the instance document, or use a parser
like Xerces and turn on PSVI augmentation so that the JAXB unmarshaller
sees those attributes as if they are present.
I'm sorry for any inconvenience this may cause.
regards,
--
Kohsuke KAWAGUCHI 408-276-7063 (x17063)
Sun Microsystems kohsuke.kawaguchi_at_sun.com