Java/Axis Null Response in windows phone 7

I am new in windows phone and using java/Axis web services.
My response properly coming to server side and server generating response properly but i am not able to see get response at my end its always show null object

my code and used url is given below :

trying to login using web-services by URL
https://www.yes-pay.net/storemanager/services/StoreManagerService

its Java/Axis web service

Button code is Like :

private void BtnLogin_Click(object sender, RoutedEventArgs e)
{
StoreManagerServiceClient _storeMgr = new StoreManagerServiceClient("StoreManagerService");
LoginRequest _lgnReq = new LoginRequest();
_lgnReq.userName = txtUserName.Text;
_lgnReq.password = txtpassword.Text;
_lgnReq.role = "M";
_lgnReq.applicationType = "M";
_lgnReq.valid = true;

_storeMgr.loginCompleted += new EventHandler(_storeMgr_loginCompleted);
_storeMgr.loginAsync(_lgnReq);
}

void _storeMgr_loginCompleted(object sender, loginCompletedEventArgs e)
{
//throw new NotImplementedException();
if(e.Result == null)
MessageBox.Show("Null Hai");
else
{
MessageBox.Show(e.Result.lastLoginDate.ToString());
// this line giving me error
}

}