[AndrianG]

Спасибо все получилось. Вот скипт для других:

static void ag_FTPex1(Args _args)
{
    TextBuffer tb;
    System.Net.WebRequest ftp = System.Net.WebRequest::Create(ftpAddress);
    System.Net.FtpWebRequest request;
    System.Net.NetworkCredential credential = new System.Net.NetworkCredential(user, password);
    System.Net.FtpWebResponse response;
    Object o;
    System.IO.Stream stream;
    System.Byte b;
    System.Text.Encoding e;
    ;
    try
    {
        o = ftp;
        request = o;
        request.set_Credentials(credential);
        ftp.set_Method("APPE");
        e = System.Text.Encoding::get_Default();
        stream = ftp.GetRequestStream();
        stream.Write(e.GetBytes("12\n"), 0, 3 );
    }
    catch
    {
        info ('FTP connection failed');
    }
    if (stream)
    {
        stream.Close();
    }
    if (ftp)
    {
        ftp.Abort();
    }
    pause;
}