I have my TIM sim from last year and I've grown quite fond of it, really

.....I just wish I could recharge online. I'm registered to access my account online but in the directions it says in order to recharge online, I need a credit card that was issued in Italy. I think that's rather ridiculous but are they real strict about it? If I try to do it anyway with my American credit card will it just be denied? That really sucks

if it's true!!! Cuz it would be SO MUCH EASIER to recharge online instead of having to go to the tobacco shops all the time when in Italy.
Also, I know this is a prepaid forum, but are there postpaid options in Italy???? That is, if I were to go there longterm, I'd probably want a post-paid account (or not, I dunno!)