Are you referring to Chinotto? I love that stuff. I wish I could get the less sweet versions, but I always buy a few cases of Brio anytime I go home to Toronto.
The cedrata is made with Citrus Medica or Citrus Diamante. This is basically a larger and sweeter (less acid) lemon.
The chinotto is made with Citrus Mirtyfolia. This is basically a small, bitter orange.
If this keeps up, I'm going to become an italian soda smuggler.
What you can do (at home) is to make it yourself, there are good chinotto syrups and you just add sparkling water to make a chinotto that is better than the pre-made soft-drinks.