Ok, I changed the hidden field to a variable ($faktutrakning) (thanks for the tip). I understand that I need to put the value from the "$faktutrakning" variable in to the cart. Do I just write "<?php echo $faktutrakning; ?>" in the eCart Add from Recordset -server behaviour?
Now, do I have to make a new column in the cart in where to store this value, should I call this column "Shipping"? Or how would I get this value to the Shipping column so that it would be automatically inserted in various right places on the checkout pages?