Use "attachClasses" in the WAR plugin so that it is possible to use overlays and WAR dependencies to extent the Roller WAR (see also http://www.ensor.cc/2011/07/mavens-war-overlays-how-to-manage.html)

git-svn-id: https://svn.apache.org/repos/asf/roller/trunk@1491240 13f79535-47bb-0310-9956-ffa450edef68