If your store uses DIBS to manage payments, then the risk is that you have to worry about characters like åäö.

What we had to do is to make the form post the data as ISO-8859-1.
We did this by adding accept-charset=”iso-8859-1″ to the forms that we send to DIBS.

In “/app/design/frontend/default/blank/template/dibs/standard/redirect_paymentwindow.phtml”

56

<form action="https://payment.architrade.com/paymentweb/start.action" method="post" name="dibs" id="dibs" accept-charset="iso-8859-1">

Once we had done this then the order details were shown correctly on the DIBS page (yes, the Chinese chars are just a test, I have no idea what it might say)