Excel Addin : calling service

Given a simple asmx service, here is how to call it in an Excel AddIn

(...)
using ExcelAddIn.ServiceReference1;

namespace ExcelAddIn
{
    public partial class ThisAddIn
    {

        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
        }

        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
        }

        public void Hello()
        {
            using (Service1SoapClient svc = new Service1SoapClient())
            {
                Excel.Range rgStart;
                Excel.Worksheet ws = (Excel.Worksheet)Globals.ThisAddIn.Application.ActiveWorkbook.ActiveSheet;
                rgStart = ws.Application.ActiveCell;
                rgStart.Value2 = svc.HelloWorld();
            }           
        }


        #region VSTO generated code

        /// 

        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// 
        private void InternalStartup()
        {
            this.Startup += new System.EventHandler(ThisAddIn_Startup);
            this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown);
        }
        
        #endregion
    }
}

In RibbonBar

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Office.Tools.Ribbon;

namespace ExcelAddIn
{
    public partial class Ribbon1 : OfficeRibbon
    {
        public Ribbon1()
        {
            InitializeComponent();
        }

        private void Ribbon1_Load(object sender, RibbonUIEventArgs e)
        {

        }

        private void button1_Click(object sender, RibbonControlEventArgs e)
        {
            Globals.ThisAddIn.Hello();
        }
    }
}