Farfallina, I don't know how to do an internet search for your locality but you might try to find powdered buttermilk or buttermilk powder, dried buttermilk, etc.
I tried to find the post that a member of another forum, who lives in Israel, made about finding it but so far no luck.
The company that makes it for both commercial kitchens and consumers here in the US is SACO. There are other producers but they are small, mostly local, organic, etc.