[SOLVED] Icelandic characters in alphabetical order

I'm having trouble with the order of my posts. They are in alphabetical order (not time order) but the special icelandic characters (á, ð, é, í, ó, ú, þ, æ, ö) are not in the right place. The icelandic alphabet looks like this:

A Á B C D Ð E É F G H I Í J K L M N O Ó P Q R S T U Ú V W X Y Ý Z Þ Æ Ö

How can I order my posts in icelandic alphabetical order?