Plugin doesn’t support Scandinavian letters

I’m testing out a contact form plugin in WP, but I have encountered a problem: The e-mails won’t display Scandinavian letters (like “æ”, “ø” and “Ã¥”). This is rather essential for meg, so I need to edit the code to make it work properly. How do I make these letters display correct in my e-mails? I have gotten some help, and I’ve already tried the following:

Added this line in the PHP-document:
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> (or charset “iso-8859-10”)

Changed the line
$encoding = get_option('blog_charset');</code
to
$encoding = 'iso-8859-1'; (or "utf-8")

Nothing of the suggested helps. Besides, I've already chosen "UTF-8" in the WP options.

Is there any way to solve this?

Thanks in advance!