Hotmail duplicates Mail in sent folder

Hi, I'm using Hotmail with Mail-program on my MacBook Pro. However, I have a problem that all my sent e-mails are duplicating themself in the sent folder.

I have done some research about the topic, and found a possible solution in this thread. Anyways, I am not happy with the result yielded by the procedure.

If I follow the approach both the mails will dissappear. But if I sent a new one after folowed manual, that one would be there, in only one copy. But then there is not stored anything in the Hotmail-web-interface, where I'd also like to have them. Both for backup, and because a sometimes send mails directly from the web-service and then it is nice that they are syncronized to the Mail.app as well.

I have tried to set up the mail account from scratch again, but it didnt help. I've also gone through the settings in the hotmail-web-interface, but couldnt find anything i thought would help.

Okey, have anybody else experienced this. And are there any suggestions for how it can be solved?

Jared