Hello accounts103,
You are able to set up a new term, however the only options you are given are either 'Due in fixed number of days', 'Due by certain day of the month' or 'Due the next month if issued within'. You can set a new term up by going to the cog wheel > All lists > Terms > New. You could also select the due date manually if you are not able to set up the term you need.
Thanks,
Talia
