At some point I wanted to solve http://bugs.dwscoalition.org/show_bug.cgi?id=2180 but I don't really understand how the translation system works (or why it doesn't work in this case) so any clue would be great.

If I remember correctly, basically what that means is even though the code behind it got changed, it was already loaded into the system, and the system doesn't overwrite existing translation strings. I poked denise into changing it on the site's translation interface--sorry if that stole it, but it was something easier to fix there than in the code. Now, if you wanted to fix it in the code, you could, but it's kinda crufty: you have to change the name of the translation string in the translation file and where it gets used. Usually people add a "2" on, or something. (If you see translation string names with 2 on the end, now you know why.)

I added the one you suggested, and I'll see about looking into whether or not the thing listed could be done simply with S2! (I'll have to look at the existing built in S2 functions, methinks.)