Of course there are white fragance violets ! Odorata alba, odorata c'zar blanc for example :-)Really easy going girls :o) I do wonder what kind of violet you bought if they were called odorata et hadn't any smell !!
The best thing to do is to buy fragance violets in a nursery selling them: Groves for example :o)
About Swedish winter and growing violets: well...I'm not sure it's the better place...

All the best :-)
Thierry.

I'm guessing it would be very difficult (restrictions and such) to ship you a piece of the plant itself??? But if it isn't problematic, I could probably even do that.
Tom