Fixed it by upgrading to version 1.6
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>jaxb2-maven-plugin</artifactId>
<version>1.6</version>
</plugin>
and
<!-- JAXB GENERATOR PLUGIN -->
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>jaxb2-maven-plugin</artifactId>
<version>1.6</version>
....
Fixed in version 1.6, in version 1.5 all execution blocks were using the same staleFile: http://jira.codehaus.org/browse/MJAXB-8