If you don't take the warranty upon purchase, it's normal that they don't want to sell it over the phone, it's part of the requirements that the device must be taken to an Apple store within the first month for inspection. After that first month you can't get the AC+ anymore. At least that's what I've read on Apple website.
As for how many time it takes to show up, I can't tell, but as long as you have your bill for both the device and the warranty, I don't think you have to worry about that. Although I guess I understand that you'd feel better if you could see it there.
I just bought it too... Didn't take the AC+ finally, as I intend to sell over to get the next iPhone. I just didn't had a choice, my gf's 3GS just died so I gave her my 4, and I couldn't find a good and quick sell on the 4S in the aftermarket, and I'm not that patient when it comes to Apple products - as soon as I decided I'd get a 4S, it was only a matter of hours before I needed to HAVE it in my hands, and see how much better it was. Got the iPad 3 two weeks later, another head rush...

Now I'm broke, I'll have to scratch everything to get the new iPhone - of course I won't sell the 4S before I get to hold the 5.
I assume you decided you'd keep the 4S over the next gen, as you took the AC+... Sometimes I think I'll do that too... And then, many times I just can't wait for the release of the next. What was it that got you to decide to get the 4S now?
Sorry... talk too much, and I didn't even answer the question...
