JBoss uses the log4j.xml which is present in %JBOSS_HOME%/server/< serverName>/conf folder. Add your configurations to that JBoss file.
thanks for your reply.
is it possible to have a seperate log4j.xml file for my EJB project? If so what are the configurations needs to be done?
See this http://www.jboss.org/community/docs/DOC-12003
If moving to JBoss-4.2.x version is possible for you, then let us know - there's a forum thread which contains the steps required to configure your own log4j.xml for JBoss-4.2.x