Java Card

Dear All,
We are developing a client application that should communicate with the Utiba Uchoose Server. According to the Utiba spec we have to send,

2-byte length header in Binary format (Network byte order)
(Note: this length header denotes the number of bytes in the message body only)
AND
Message body in ASCII format.

Inorder to communicate with the server we developed a sign on application using jPos. But the response is null. I am providing the code we have developed.

package lk.dialog.ezi.api;

import java.util.Date;
import java.io.PrintStream;
import org.jpos.util.*;
import org.jpos.iso.*;
import org.jpos.iso.packager.*;
import org.jpos.iso.channel.ASCIIChannel;
import org.jpos.iso.header.BaseHeader;
import java.nio.*;


public class SignOnTest implements Runnable {
    ASCIIChannel channel;
    ISOMUX mux;
    public void setupMUX () {
        ISOPackager packager = new ISO87APackager();
        channel = new ASCIIChannel("192.168.70.82", 17001, packager);
        mux = new ISOMUX (channel);
        Thread t = new Thread (mux);
        t.start();
    }
    public void run () {
            ISOMsg m = new ISOMsg();
                try{
                    m.setMTI("0800");
                    m.set(new ISOField(7, ISODate.getDateTime(new Date())));
                    m.set(new ISOField(11, "000001"));
                    m.set(new ISOField(70, "061"));
                    m.set(new ISOField(100, "123456"));
                    m.setPackager(new ISO87APackager());
                    byte[] messageBody=m.pack();
                    short messageLength=(short)messageBody.length;
                    ByteBuffer bb=ByteBuffer.allocate(2);
                    bb.putShort((short)messageLength);
                    bb.flip();
                    byte[] header=bb.array();
                    BaseHeader bh=new BaseHeader(header);
                    m.setHeader((ISOHeader)bh);
                    ISORequest req = new ISORequest(m);
                    mux.queue(req);
                    ISOMsg res = req.getResponse(60*1000);
                    if (res != null) {
                        res.dump(System.out, "");
                        System.out.println(res.getString(39));
                    }
                    else{
                        System.out.println("Response is null");
                    }
                    mux.showCounters(System.out);
                } catch (ISOException e) {
                    e.printStackTrace();
                }
    }
    public static void main (String args[]) {
        SignOnTest test = new SignOnTest();
        test.setupMUX ();
        (new Thread(test)).start();
    }
}

############Output Result##########
Response is null
Connections: 1
TX messages: 1
TX expired: 0
TX pending: 0
RX messages: 0
RX expired: 0
RX pending: 1
RX unmatched: 0
RX forwarded: 0

Please help me to get around this problem. Thanks in advance.