There is a fix that was change into upstream that makes ejb shutdown more graceful. Combined with @DependsOn this should resolve the issue.
Give the latest snapshot a try:
http://hudson.jboss.org/hudson/view/JBoss%20AS/job/JBoss-AS-7.x-latest/lastSuccessfulBuild/artifact/build/target/jboss-as-7.x.zip