It seems to be fixed in current version of maven-war-plugin, so just specifying:
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>2.3</version>
</plugin>
fixed it for me. (See the last answer (20/Sep/12 4:37 AM) from Anders Hammar on https://issues.apache.org/jira/browse/MWAR-248.)