[Plugin: Attachments] Problem with Swedish characters (åäö)

I’m using the plugin Attachments by jchristopher and it works great except from one thing and that is that Swedish characters like å, ä and ö show up as “Ã¥” as well in Admin as front-end.

I’m guessing that this could have something to do with the fact that the plugin uses Base64 encoding but my PHP-skills are far to moderate to be speculating in such matter.

Any help and ideas are appreciated.