How to consume AX dynamics web service in windows phone 8.1 universal app

Question

I tried consume a AX dynamics secured web service in windows phone universal app. But i am unable to do so as windows phone run-time doesn't support service models(i.e. It doesn't provide option to add service reference). Hence Microsoft has proposed a work around using HttpClient Class.

So i did the following:

using (HttpClient client = new HttpClient())
        {
            HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, "http://xxxxx/xppservice.svc/GetData");
            HttpResponseMessage response = await client.SendAsync(request);
            string data = await response.Content.ReadAsStringAsync();
            var dialog = new MessageDialog(data);
            await dialog.ShowAsync();
        }

But the problem here is, the service which i am using is secured and i have the authentication credentials. But i am unable to figure out how supply them while sending the request. Can you please help me? A