JBoss AS 7 actually uses JBoss Log Manager to configure logging and not log4j. What version of JBoss AS/EAP are you using? If it's EAP you might want to try to add -Dorg.jboss.as.logging.per-deployment=false if you include a log4j configuration file or a logging.properties file in your deployment, but want to use the logging subsystem to configure logging.
To see some debug output you can add a logger with the category org.jboss.as.logging.
James R. Perkins