Italo until the end of the year?

No, not for Trenitalia but Italo is new start up rail system and they may be doing that. Use your credit card and see what happens. Make sure you are following the European date system - d/m/y - so it does think you are using another month.

If you are not sure, just call. They are quite helpful on the phone. the number is (011) 39 06 07 08. This call was made from Canada.
Good luck!

I finally found a spot on their website that confirms that you can buy tickets on all trains up until Dec. 14th.
I guess I'm going to buy them. I rode Trenitalia on a trip last year but since I see nothing that would keep me from using this company, I'm going for it!

Just last night I booked tickets for a July trip to Italy using Italo's very easy-to-use website. In the past we have always purchased tickets once in Italy but I wanted to take advantage of the cheaper advance tkt prices. I had registered with Trenitalia's website but decided I didn't want to mess around with them as it sometimes works and sometimes doesn't. So far I have purchased tkts for Venice to Florence and Florence to Naples. Today will purchase Naples to Rome tkts. It will assign you seats but will give you the opportunity to change seat assignments. Very easy to do. Note: I had called my Capital 1 cc in advance to notify that I would be bkg accommodations in Italy and then called them two nights ago and specified I would be making purchases through ITALO. I go through the entire bkg and cc refused. I was mad. Called Cap. 1 and yes they had refused it and had no record of my calls informing them of my upcoming overseas purchases. I rebooked and went through no problem.

I booked our tickets and was very pleased with how easy it was compared to Trenitalia's site.