Asterisk and Java AGI

I dont know if this is the right forum for questions but i am having problem with Asterisk and java AGI.
i am using 1.8 version but in queues i want to use AGI with Java and Use the memberinterface variable, i have set the variable in queue.conf setinterfacevar=yes
but still this memberinterface is coming blank. like in following extension.conf line.
exten => 4321,2,Queue(BNCC,caseStatus.agi,${MEMBERINTERFACE})

what am i doing wrong? if i put the the ${EXTEN} in it, that is showing but not the memberinterface.
my agi file looks like this

#some examples to set the class path
JAVA_SCRIPTS=caseStatus.jar #add any jar that you need
memberInterface= ${MEMBERINTERFACE}

#exec the Java VM
java -jar $AGI_DIR/$JAVA_SCRIPTS $1

even if i put ${MEMBERINTERFACE} instead of $1 or $memeberinterface, its still blank.
can anyone help? thanks

the cli console shows
Executing [4321@user:1] Ringing(“SIP/user-00000004”, “”) in new stack
– Executing [4321@user:2] Queue(“SIP/user-00000004”, “BNCC,caseStatus.agi,”) in new stack

where comma after .agi should be the agentid who picked the call