Binary XML storage can also be combined with an XML Schema. As shown in Mark Drakes presentation whitepaper (slide 6), the lower right of the diagram, shown below, marks the section for XML Schema (structured, schema based) binary XML storage.
Slide 6 of “Oracle Database 11g XML DB Presentation (PDF) July 2007”
Click picture to enlarge
The following example will show how you can create an XMLType table making use of a defined XML Schema and how to avoid the ORA-44424 error (BINARY XML storage requires XML Schema registered for BINARY usage).