I have 50 achievements to upload to iTunes Connect. I have read that you can do this using iTMSTransporter however I cannot find references or examples of the script or metadata.xml file.
I have found the file here:
You can download metadata specifications and the
from iTunes Connect: https://itunesconnect.apple.com:
You can also get help by executing
iTMSTransporter -help [command].
While I'm not familiar with uploading achievements I've written a Ruby gem that contains a small command line program that might help you:
I also have a GUI (still somewhat rough around the edges) that might help: https://github.com/sshaw/itunes_store_transporter_web/sshaw/itunes_store_transporter_web#readme