JQuery Validation Plugin addmethod

JQuery Validation Plugin addmethod

I have make addmethod for Validation Plugin but is always showing true. I don't what is the problem. I cheked in Firebug it is returning correct result and also sending correct text. But still companyNameCheck method behaving wired. Following is my JQuery Code

  1.         $("#frmCompany").validate({
              rules:
              {
                fvCompany$txCompanyName:
                {
                  required: true,
                  companyNameCheck: true
                },
                fvCompany$txTelephone1:
                {
                  number: true,
                  minlength: 8
                },
                fvCompany$txTelephone2:
                {
                  number: true,
                  minlength: 8
                },
                fvCompany$txFax:
                {
                number: true,
                minlength: 8
                },
                fvCompany$txEmailID:
              {
                email: true
              }
              },
              messages:
             {
               fvCompany$txCompany_Name:
               {
                 required: "Provide Company Name",
                 companyNameCheck: "Company already exits"
               },
               fvCompany$txTelephone1:
              {
                number: "Only digits are allowed",
                minlength: jQuery.format("Enter at least {0} digits.")
              },
              fvCompany$txTelephone2:
              {
                number: "Only digits are allowed",
                minlength: jQuery.format("Enter at least {0} digits.")
              },
              fvCompany$txFax:
              {
                number: "Only digits are allowed",
                minlength: jQuery.format("Enter at least {0} digits.")
              }
             },
              success: function (label) {
                // set   as text for IE
                label.html(" ").addClass("positive");
              },
              errorPlacement: function (error, element) {
                error.appendTo(element.parent().next());
              }
            });
          });

         
          jQuery.validator.addMethod('SelectNone', function (value, element) {
            return this.optional(element) || (value.indexOf("-- Please Select --") == -1);
          }, '');

          jQuery.validator.addMethod('companyNameCheck', function (companyName) {
            var postURL = "WebService.asmx/GetExactCompany";
            $.ajax({
              cache: false,
              async: false,
              type: "POST",
              url: postURL,
              data: "{'companyName':'" + String(companyName) + "'}",  //data
              contentType: "application/json; charset=utf-8",
              dataType: "json",
              success: function (msg) {
                result = (msg == "1" ? true : false);
              }
            });
            return result;
          }, '');
















































































This is my Webservice Webmethod

  1.  <WebMethod()> _
      Public Function GetExactCompany(ByVal companyName As String) As String
        Dim available As String = ""
        Dim companyAPI As New CompanyBLL
        Dim company As HelpDesk.CompanyDataTable = companyAPI.GetCompanyByExactCompanyName(companyName)

        Try
          If company.Rows.Count > 0 Then
            available = "0"
          Else
            available = "1"
          End If

        Catch ex As Exception
          'Setup a breakpoint here
          'to verify any exceptions raised.
          Dim exp As String = ex.ToString()
        End Try
        Return available
      End Function




















Above is used in asp.net 4.0 in FormView InsertTemplate. Can somebdoy tell me what wrong I might be doing