Java – HTTP/1.1 407 error with latest Apache HttpClient 4.1.1 when using NTLM authentication

I'm trying to use the Apache HttpClient 4.1.1 library (http://hc.apache.org/httpcomponents-client-ga/tutorial/html/authentication.html) to access sites from behind my company's proxy that uses the ISA Server with NTLM authentication but I keep getting an HTTP 407 Proxy Authentication Required error:

Code Snippet

    HttpHost proxy = new HttpHost("myProxyHost", 80, "http");
    DefaultHttpClient httpClient = new DefaultHttpClient();
    httpClient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);

    NTCredentials creds = new NTCredentials("myWindowsUserName", "myWindowsPwd", "localhost", "myCompanyDomain");
    AuthScope authScope = new AuthScope("myProxyHost", 80, "", "NTLM");
    httpClient.getCredentialsProvider().setCredentials(authScope, creds);

    HttpHost target = new HttpHost("www.google.com", 80, "http");
    HttpGet get = new HttpGet("/");
    System.out.println("executing request to " + target + " via " + proxy);
    HttpResponse rsp = httpClient.execute(target, get);

    System.out.println("----------------------------------------");
    System.out.println(rsp.getStatusLine());
    Header[] headers = rsp.getAllHeaders();
    for (int i = 0; i<headers.length; i++) {
        System.out.println(headers[i]);
    }
    System.out.println("----------------------------------------");

O/P

executing request to http://www.google.com:80 via http://myProxyHost:80
----------------------------------------
HTTP/1.1 407 Proxy Authentication Required ( The ISA Server requires authorization to fulfill the request. Access to the Web Proxy filter is denied.  )
Via: 1.1 myCompanyServer
Proxy-Authenticate: Negotiate
Proxy-Authenticate: Kerberos
Proxy-Authenticate: NTLM
Connection: Keep-Alive
Proxy-Connection: Keep-Alive
Pragma: no-cache
Cache-Control: no-cache
Content-Type: text/html
Content-Length: 4120  
----------------------------------------

What am I missing here?

Update:
In the same environment, code using the JDK URL and URLConnection classes works!

Working Code Snippet

    System.setProperty("http.proxyHost", "myProxyHost");
    System.setProperty("http.proxyPort", "80");

    URL url = new URL("http://www.google.com");
    URLConnection con = url.openConnection();
    BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
    String inputLine;
    while ((inputLine = in.readLine()) != null)
        System.out.println(inputLine);
    in.close();

O/P

Google window.google={kEI:"_N3cTaLFMY6cvgOH9MypDw",...