axis2-java2wsdl-maven-plugin NullPointerException

Hello,

I was just wondering, according to the page
http://axis.apache.org/axis2/java/core/tools/maven-plugins/maven-java2wsdl-plugin.html

the plugin can be invoked directly by doing a

mvn axis2-java2wsdl:java2wsdl

However, this fails with a null pointer execption.

If I do a "mvn package" I can see that the plugin goal is executed. And
some mocking about showed me that "mvn process-classes
axis2-java2wsdl:java2wsdl" also works.

Now, im confused, the docs says that the goal is tied into
generate-resources, but it seems to require the process-classes phase?
Whats going on? Why doesn't the command hinted by the documentation work?

Best regards,
Daniel