Try editing the local messages file as talked about in this thread. There's also more good info in this post.

I don't know what the utility is to generate a msgso file. I feel like it ought to be something obvious, but, as a USAian, I hardly ever have to deal with it, so I just don't know. Nor do I know if we have enough information to replroduce it anyway. Probably not.

But you should be able to edit it by hand. My only caveat is that the strings are probably length-specific, so if the Italian word is longer, use an abbreviation to keep it no longer than what's currently there.