How to pass the startup options in JBoss EAP 6 linux service?

Issue

• Using jboss-as-standalone.sh it is possible to change the standalone directory location?
• Is there a way to change the standalone directory location other than standalone.conf file?
• I tried with jboss-as-standalone.sh amending it as below, Could you tell us the correct way to change in jboss-as-standalone.sh?

JBOSS_SCRIPT="$JBOSS_HOME/bin/standalone.sh -Djboss.server.base.dir=/jboss/sample/eap/sample_standalone

--host-config=/jboss/sample/eap/sample_standalone/configuration/standalone-full.xml

• Start the JBOSS EAP 6.4 service with standalone-full-ha.xml configuration file. Could you please help me to start the JBOSS EAP 6.4 service with standalone-full-ha.xml configuration file. I tired with the below setting but that didn't works for me. Under the file /home/test/server/bin/standalone.conf, I update the configuration file setting as below :

if [ "x$JAVA_OPTS" = "x" ]; then
JAVA_OPTS="-Xms1303m -Xmx1303m -XX:MaxPermSize=256m -Djava.net.preferIPv4Stack=true"
JAVA_OPTS="$JAVA_OPTS -Djboss.modules.system.pkgs=$JBOSS_MODULES_SYSTEM_PKGS -Djava.awt.headless=true -c standalone-full-ha.xml "
   JAVA_OPTS="$JAVA_OPTS -Djboss.modules.policy-permissions=true"

• What is the preferred location to set JAVA_HOME for jbossas service of EAP 6 , where EAP 6 service is installed by default on Linux based O.S. as RPM method of installation? If the JAVA_HOME is set inside /etc/init.d/jbossas service script to a Java version installed on the system (which is installed as an RPM method as well) what could be the challenges involved in such approach?