I just did some searching on google.no I cannot find any people selling them so you'ld have to find someone local to go gather them next year, and I expect importing would be illegal. You don't need to go very far north in Norway to hit zone 6 just inland, same for most of europe you could also look for seeds from Poland and most of Eastern europe. I've not managed to get any seeds to germinate for me here

Think I will have to try cuttings instead, as the plants are not mine I can't try layering which I know is easy.