使用HttpWebRequest在服务器上创建目录

我试图通过https在服务器上创建目录。但是，在返回响应时，它会生成异常:"远程服务器返回了一个错误:(404)Not Found。"代码如下:

string szURL3 = @"https://directoryurl/TestDir/";
//Create an HTTP request for the URL.
HttpWebRequest httpMkColRequest = (HttpWebRequest)WebRequest.Create(szURL3);
// Set up new credentials.
httpMkColRequest.Credentials = new NetworkCredential(_httpsUserName, _httpsPassword);
// Pre-authenticate the request.
httpMkColRequest.PreAuthenticate = true;
// Define the HTTP method.
httpMkColRequest.Method = @"MKCOL";             
// Retrieve the response.
HttpWebResponse httpMkColResponse = (HttpWebResponse)httpMkColRequest.GetResponse();
//Write the response status to the console.
Console.WriteLine(@"MKCOL Response: {0}",httpMkColResponse.StatusDescription);

有人能支持这一点吗?我可以用同样的方法正确地获取目录信息。正如我提到的一些链接:http://blogs.msdn.com/b/robert_mcmurray/archive/2011/10/18/sending-webdav-requests-in-net-revisited.aspx根据这个，我理解的是资源被锁定了。但是如何解锁创建目录的资源。