AS3 and .NET Web Services

I need to POST vars to a .NET Web Service but it don´t work. On the server side (.NET) I will receive the posted vars. So how do I send the POST-vars from Flash and do I receive it in .NET?

The web service below is just a test:

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml.Linq;

using System.IO;

namespace FileUploader
    /// <summary>
    /// Summary description for UploadService
    /// </summary>
    [WebService(Namespace = "")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    // [System.Web.Script.Services.ScriptService]
    public class UploadService : System.Web.Services.WebService
        public string SaveFile()
            String responseStr;
            if (System.Web.HttpContext.Current.Request.Form["test1"] != null)
                responseStr = "test1 was Not null";
                responseStr = "test1 was null";
            return responseStr;