ÅÄÖ characters missing when printing

I have made a translation to swedish using a separate .mo file. However, when printing the invoice and shipping the characters åäö is missing. This also goes for the information entered in the module settings. When I preview the templates in the module admin everything looks ok, but not when printed. How come?

http://ww.wp.xz.cn/plugins/woocommerce-delivery-notes/