I tried to reproduce this, but ended up with a different error. The way I made it work was to add the following to echo/src/main/webapp/WEB-INF/spring-ws-servlet.xml:
I did a mvn package after that, and copied the target/echo.war to jboss-4.2.0.GA/server/default/deploy/. Let me know if this solution works for you. Both clients (saaj and spring-ws) work with this setup.
<bean id="messageFactory" class="org.springframework.ws.soap.saaj.SaajSoapMessageFactory">
<bean class="com.sun.xml.messaging.saaj.soap.ver1_1.SOAPMessageFactory1_1Impl" />
I'll add an entry to the FAQ about this.