Jetty Maven Plugin is ignoring custom webdefault.xml

I found an entirely different doc for the newer Jetty plugin jetty-maven-plugin (v8.0.0.M2) and it looks like the configuration name has changed:

http://wiki.eclipse.org/Jetty/Reference/webdefault.xml#Using_the_Jetty_Maven_Plugin

<project>
    ...
    <plugins>
        <plugin>
            ...
            <artifactId>jetty-maven-plugin</artifactId>
            <configuration>
                <webAppConfig>
                  ...
                  <defaultsDescriptor>/my/path/to/webdefault.xml</defaultsDescriptor>
                </webAppConfig>
            </configuration>
        </plugin>
        ...
    </plugins>
    ...
</project>

This now seems to work for the newer plugin. I'm still unsure why the v6 plugin does not pick up the customized config.

The only solution I found that worked with maven-jetty-plugin 6.1.24 was this: http://false.ekta.is/2010/12/jettyrun-maven-plugin-file-locking-on-windows-a-better-way/