"Due" field in ticket creation form doesn't work

Tickets created via WebRT always get the due date set to the time of
ticket creation, ie. RT honors neither the content of the “Due” form
field nor the queue configuration (which says tickets should be due 7
days after creation).
When creating tickets via mail, this 7 day interval works fine.

Any suggestions?
I’d rather not have to run after my users fixing due dates and
priorities (which, in consequence, get messed up by escalator).

Sebastian Flothow
#include <stddisclaimer.h>