keystore problem with iseries java pgm making SSL connection to another site

I have the following java pgm running in a q-shell.
It is attempting to connect to another site via https, and needs to
identify itself with a certificate issued by the other site (Motorweb).
The certificate is in PKCS12 keystore format, but program execution fails
at the commented line with:

 java.io.IOException: Keystore type is invalid


Any ideas?


----------------------------------------------------------------------------------------------------------------------------------------


import java.util.*;
import java.net.*;
import java.io.*;
import javax.net.ssl.*;
import javax.security.cert.X509Certificate;
import java.security.KeyStore;


public class TestMotorWeb {

            /**
            * This example shows how to send a motorweb https request with
client side
            * authentication. Requires Java 1.4
            *
            *
            */
        public static void main(String[] args) throws Exception {

          String URLstr = null;
          String ClientCertFileName = null;
          String XMLFileName = null;
          String ClientCertPasswd = null;
          long startTime = System.currentTimeMillis();
          // submit to test URL
          URLstr = "
https://www.motorweb.co.nz/action/robotLoadVir/1.0?reference=e2f93d0f";;
          ClientCertFileName = "/java/hnzdev/motorweb.p12";
          ClientCertPasswd = "notreallymypassword";
          try {
            // set up a key manager so that we can do client authentication
            // if asked by server
            SSLSocketFactory factory = null;
            try {
              SSLContext ctx;
              KeyManagerFactory kmf;
              KeyStore ks;
              // Password on p12 file
              ctx = SSLContext.getInstance("SSL");
              kmf = KeyManagerFactory.getInstance("IbmISeriesX509");
              ks = KeyStore.getInstance("PKCS12");
              //load p12 client certificate file
              char[] passphrase = ClientCertPasswd.toCharArray();
              ks.load(new FileInputStream(ClientCertFileName), passphrase);

// The following line is failing with " java.io.IOException: Keystore type
is invalid "
              kmf.init(ks, passphrase);
              ctx.init(kmf.getKeyManagers(), null, null);
              factory = ctx.getSocketFactory();

            } catch (Exception e) {
                  throw new IOException(e.getMessage());
            }
            // start up https connection
            HttpsURLConnection.setDefaultSSLSocketFactory(factory);
              URL g2b = new URL(URLstr);
              startTime = System.currentTimeMillis();
              System.out.println("startTime="+startTime);
              URLConnection connection = g2b.openConnection();
              connection.setDoOutput(true);
              connection.setUseCaches(false);
              // This is probably redundant but set anyway
              connection.setRequestProperty("Connection", "Keep-Alive");
              // Read in the result and write to standard out
              BufferedReader in = new BufferedReader( new
InputStreamReader(connection.getInputStream()) );
              String inputLine;
              while ((inputLine = in.readLine()) != null) {
                System.out.println(inputLine);
              }
              in.close();

System.out.println("FinishTime="+(System.currentTimeMillis()-startTime));
          } catch (Exception e) {
          e.printStackTrace();
        }

  }
}