I had the same problem and did the following, after which everything worked just fine:
copy commons-logging.jar from $JBOSS_HOME/server/all/lib to $JBOSS_HOME/server/your_current_config/lib
copy jax* from $JWSDP_HOME/common/lib/ to $JBOSS_HOME/server/your_current_config/lib
I found you also had to copy the jar file $JWSDP_HOME/common/lib/saaj_ri when deploying the jaxrpc HelloWorld example when using Jetty as opposed to Tomcat.
Add saaj-api.jar and dom4j.jar to the list of required archives to move from jwsdp to jboss when running saaj-simple.war example in jetty.
These jars are easy to find...they are one of the few files that doesn't start with a 'j'.