Rapaport TechNet
 
HTTP POST/WebClient (C#) and CSV file

string URLAuth = "https://technet.rapaport.com/HTTP/Authenticate.aspx";
WebClient webClient = new WebClient();

NameValueCollection formData = new NameValueCollection();
formData["Username"] = "myUser";
formData["Password"] = "myPassword";

byte[] responseBytes = webClient.UploadValues(URLAuth, "POST", formData);
string ResultAuthTicket = Encoding.UTF8.GetString(responseBytes);

webClient.Dispose();
string URL = "http://technet.rapaport.com/HTTP/Upload/Upload.aspx?Method=file&ReplaceAll=false&ticket=" + ResultAuthTicket;
formData.Clear();

responseBytes = webClient.UploadFile(URL, "POST", "C:\\test.csv");
string Result = Encoding.UTF8.GetString(responseBytes);