I HATE "MY Disney Vacation" website. You have a user name and you think your reservation would be attached to it, but you have to enter in your reservation # and phone # for it to come up. For last year's trip it came up in My Itineraries but not this year.
How long did you wait to check the website after you made the reservation? and did you get an email confirmation? You should be able to access it through a link in your email too.
Hope you can get it!