How can I force the Maven EAR plugin to use a cont

I'm using the Maven EAR plugin to generate the application.xml of my EAR, which contains a WAR.

I want the contextRoot of that WAR to be determined at runtime (this works thanks to JBoss AS 7), so the application.xml should contain something like this:

<module>
  <web>
    <web-uri>my.war</web-uri>
    <context-root>${my.context.root}</context-root>
  </web>
</module>

This works by setting the System Property my.context.root within JBoss AS 7 and configuring JBoss to replace variables within XML descriptor files:

<system-properties>
    <property name="my.context.root" value="/foo"/>
</system-properties>

<subsystem xmlns="urn:jboss:domain:ee:1.1">
  <spec-descriptor-property-replacement>true</spec-descriptor-property-replacement>
  <jboss-descriptor-property-replacement>true</jboss-descriptor-property-replacement>
</subsystem>

If I do this by editing the generated application.xml in the EAR, it works.

However, I can't get Maven to write ${my.context.root} into the context root within application.xml.

I tried this first (since nothing is filtered, it should work):

<configuration>
  <modules>
    <webModule>
      <groupId>my.group</groupId>
      <artifactId>my-war</artifactId>
      <contextRoot>${my.context.root}</contextRoot>
    </webModule>
  </modules>
</configuration>

Apparently, even though filtering defaults to false, Maven still thinks it should use this as Maven property. The result is that the EAR plugin just puts in the WAR's name:

<module>
  <web>
    <web-uri>my-war.war</web-uri>
    <context-root>/my-war</context-root>
  </web>
</module>

So I tried escaping:

<configuration>
  <modules>
    <webModule>
      <groupId>my.group</groupId>
      <artifactId>my-war</artifactId>
      <contextRoot>\${my.context.root}</contextRoot>
    </webModule>
  </modules>
</configuration>

This is then taken literally:

<module>
  <web>
    <web-uri>my-war.war</web-uri>
    <context-root>\${my.context.root}</context-root>
  </web>
</module>

How can I get Maven to do what I want? (Of course, I could try to hack application.xml by using the Maven replacer plugin, but that's ugly...)

Thanks for any hints!

Well, since nobody knows a better answer, here's how I hacked application.xml into shape:

<plugin>
  <groupId>com.google.code.maven-replacer-plugin</groupId>
  <artifactId>replacer</artifactId>
  <executions>
    <execution>
      <id>replace-escaped-context-root</id>
      <phase>process-resources</phase>
      <goals>
        <goal>replace</goal>
      </goals>
      <configuration>
        <file>${project.build.directory}/${project.build.finalName}/META-INF/application.xml</file>
        <regex>false</regex>
        <token>\${</token>
        <value>${</value>
      </configuration>
    </execution>
  </executions>
</plugin>

<plugin>
  <artifactId>maven-ear-plugin</artifactId>
  <configuration>
    <modules>
      <webModule>
        <groupId>my.group</groupId>
        <artifactId>my-war</artifactId>
        <contextRoot>\${my.context.root}</contextRoot>
      </webModule>
    </modules>
  </configuration>
</plugin>