In case people were interested in newer developments on this topic, Perry kindly posted an issue on Jira: https://issues.apache.org/struts/browse/WW-2781
He also came up with a workaround: changing the DTD reference in struts.xml
from
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts
Configuration//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd";>
to
<!DOCTYPE struts SYSTEM "struts-2.0.dtd">
and putting the struts-2.0.dtd into the local class path.
