Graeme, ditto: never come across 'ad' used in this sense in GB English (my target group being speakers of everyday English and business English).
I think 're' would do nicely, and is in common usage. [Red Red Robin <GB>]
It's certainly as penguin says: "ad" in this sense is widely understood in the legal community, and frequently used, too. In my almost 20 years as a legal translator, I haven't had a single question about the use of this word, and I've regularly translated it into German from texts written by native speakers of (legal) English from all over the world. Unfortunately I can't post a single example. However, if you google for "ad item" you'll find at least one UN document... [Ute]
I (British) have used "ad" in this sense (referring to a previous numbered list) for well over 30 years. I gather it is not used in the U.S. and I have recently noticed several BE speakers claiming that they have never heard of it. I was also unable to find documentary evidence. OTOH I don't think I've seen it in German before. I always see "zu". [Mike.E]
Thanks for the clarification, penguin, and the other opinions and references. I shall provisionally categorize "ad" alongside "inter alia" and similar terms as a legal Latinism, not wrong in the proper context, but inappropriate in texts designed for a more general audience. [graeme]
A view from New York: ad is unknown in general writing in American English. It may be that it's familiar in a legal context... although as a non-lawyer, I've read a number of legal writings over the years, and don't ever remember seeing it.
(Note that "ad" is short for "advertisement" and is a familiar word with that meaning: Have you seen the new Mercedes ad? I assume that most of the Google hits will be with this meaning.) [eric (new york)]
Das ist ein Auszug aus der früheren Diskussion.
@Werner: Der Ursprung des Wortes spielt keine Rolle. Übersetzt muss es werden, denn 1) ist nicht gleich ad 1) (letzteres impliziert, dass es bereits zuvor erwähnt wurde)
@Mike E: Ad wird im Deutsche sehr häufig verwendet. "Some people" ist also ein klares Understatement.