I've added in transifex a new translation for the documentation of the terminal package. https://translations.xfce.org/projects/terminal/master/view/po-doc/it.po. I'm inserting this bug report just to ask the maintainer of the package to update the build scripts and create new directories for the output files.
I've changed the build system to automatically build the html pages from the po files. You can try it in the nick/docgen branch of terminal. This will be merged to master asap.