For server to server invocations, take a look at this https://docs.jboss.org/author/display/AS72/Developer+Guide#DeveloperGuide-EJBinvocationsfromaremoteserver.
Or if you are using EAP 6.1 or WildFly, then you can even use this approach https://docs.jboss.org/author/display/WFLY8/Scoped+EJB+client+contexts
Thanks for the response jai. The first link you gave me (https://docs.jboss.org/author/display/AS72/Developer+Guide#DeveloperGuide-EJBinvocationsfromaremoteserver) is actually
the one I followed to begin with, and it gave me security exception error. In this doc, you say to modify standalone-full.xml for security-realms stuff. I did this in host.xml. Also in the "Create a outbound-socket-binding on the "Client Server" section, it says to modify "standard-sockets", but since we are using "full-ha-sockets" in domain mode, I made that change in full-ha-sockets. I also modified remote-outbound-connection change you mentioned in "Create a remote-outbound-connection which uses this newly created outbound-socket-binding" section in full-ha profile since we are using this profile in our domain. But I'm still getting SecurityException. What did I do wrong? Thanks again.