About the UML profile for XML

[kimnico]

Hello everyone,
I am currently playing with the XSD generation functionality (described here: http://www.sparxsystems.com/resources/xml_schema_generation.html).
A 'UML Profile for XML' file is available in order to customize the schema generation, but it doesn't seem to contain the <<XSDtopLevelElement>> feature mentioned on the page. So when I try to customize a class to make it the top level element, well... I can't! Because <<XSDtopLevelElement>> is not one of the choices. I might have misunderstood some point, so I'd be glad to get some help  

Thanks in advance.