Did that resolve the issue for you? I'm currently using seedbox.fr and haven't tried to upload a torrent before. I downloaded Utorrent and did a quick upload the other day but I would before to use my seedbox since I always leave that up.
My thought on a low tech workaround =
do the initial upload on utorrent,
once it's up goto the torrent and download it using seedbox, now the file will be on the seedbox with the tracker info etc.
Leave the seedbox up and turn off utorrent.
Does a GM know if that method would work with providing me credit for the upload & seeding?