public override IFtpFolder CreateFolder(String folder, VirtualFtpSession session)
{
if (!AllowMkDir(session))
throw new FtpException(550, String.Format("Cannot create folder \"{0}\", permission to mkdir in this folder denied.", folder));
if (HasSubfolder(folder))
throw new FtpException(550, String.Format("A folder named \"{0}\" already exist.", folder));
Directory.CreateDirectory(Path.Combine(LocalPath, folder));
return new DiscFolder(this, folder, Path.Combine(LocalPath, folder));
}