Choose the terms of payment (betalningsvillkor) on the Fortnox order that tells Junipeer the order is a Svea order.
Good to know
This is shown when How do you want to identify your Svea orders? is set to Payment Method.
The list shows the values in your Fortnox. If the list is empty, check that Fortnox is connected. An empty list almost always means the connection, not the setting.
If a value is missing, create it in Fortnox first, then click Clear Cache on the settings page so the list is refreshed.