I would say that "i am not in Italy but Poland" would be an acceptable english translation (and to my ears the most natural). The 'in' before Poland is implied
English doesn't have a word like "vaan", I see you have learnt German too so it's pretty much the same as German "sondern". And you can think of 'vaan' in English as "but rather". Here's more about the difference between mutta and vaan.
Thanks for referring to German. This is a nice expansion to people who understand German.
It's utan in Swedish too :-)
I see, so it's like "mais plutôt" in French ?
I think so, but I don't think "plutôt" is compulsory in French: so in this regard French would be similar to English.
Danke schön !