I just added "download-messages" and "import-messages-from-ts" to acs-lang/www/admin on oacs-5-1 (which is the version running the translation server). Once the server has been upgraded, copy "download-messages" to the /acs-lang/www directory to make it accessible without the need to log in.
Then anyone can get the latest translations from the translation server with one click, which hopefully encourages more users to make use of the translation server.
Last but not least, once it is working this way, we could add a "Import Messages from your server" link to the translation server, which behaves exactly like import-messages-from-ts, but you can give it the URL of the server you want to import from (read: your server). As you might guess, you would have to open up your translations for download by the public first.