<system.serviceModel>
        <bindings>
            <basicHttpBinding>
              <binding name="AsapIntegrationSoapBinding" />                
            </basicHttpBinding>
            <customBinding>
                <binding name="AsapIntegrationSoap12Binding">
                    <textMessageEncoding messageVersion="Soap12" />
                    <httpTransport />
                </binding>
            </customBinding>
        </bindings>
        <client>
            <endpoint address="http://1.1.1.1:10203/Avtotransport/ws/AsapIntegration.1cws"
                binding="basicHttpBinding" bindingConfiguration="AsapIntegrationSoapBinding"
                contract="Ws.AsapIntegrationPortType" name="AsapIntegrationSoap" />
            <endpoint address="http://1.1.1.1:10203/Avtotransport/ws/AsapIntegration.1cws"
                binding="customBinding" bindingConfiguration="AsapIntegrationSoap12Binding"
                contract="Ws.AsapIntegrationPortType" name="AsapIntegrationSoap12" />
        </client>
    </system.serviceModel>

var client = new Ws.AsapIntegrationPortTypeClient("AsapIntegrationSoap");
client.ClientCredentials.UserName.UserName = "login";
client.ClientCredentials.UserName.Password = "password";
var answer = client.DownloadCheckFuelCards("70431024123472732");

System.ServiceModel.Security.MessageSecurityException was unhandled
  HResult=-2146233087
  Message=Запрос HTTP не разрешен для схемы аутентификации клиента "Anonymous". От сервера получен заголовок аутентификации "Basic realm="1C:Enterprise 8.2"".
  Source=mscorlib
  StackTrace:
    Server stack trace: 
       ...skip...
    Exception rethrown at [0]: 
       ...skip...
  InnerException: System.Net.WebException
       HResult=-2146233079
       Message=Удаленный сервер возвратил ошибку: (401) Несанкционированный.
       Source=System
       StackTrace:
            в System.Net.HttpWebRequest.GetResponse()
            в System.ServiceModel.Channels.HttpChannelFactory`1.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout)
       InnerException: