I have made a test putting the var {{var payment_html}}
inside the email template order_update.html
however when Magento sends an email using this template, any payment information is printed on the box "Payment Details". After that, I searched about it and I found out on this link that some variables don't make effect for some templates. I would like to know if is possible to show off the payment details on the order update email template.
Does anybody have idea about how to do that?