...
	if(session.IsSuccess()){
		SFtp::DirList list;
		SFtp sftp(session);
			
		sftp.Clear();
		sftp.StartListDir(directoryname,list);
		sftp.StartClose();
		if(sftp.Execute()) return true; // Reading the directory successfully proves it exists

		sftp.Clear();
		sftp.StartMakeDir(directoryname,0755);
		sftp.StartClose();
		return sftp.Execute();
	}
...