workflow edit parameter for task reminder

Hi,

i want to know if there’s a way i can add a new condition field

i want to create a task reminder (30 minute before due time) using send email
(yes i already saw this post https://suitecrm.com/forum/suitecrm-7-0-discussion/5606-workflow-question-what-does-date-now-mean#20710 )

all i can search on the forum is put this logic
due date <= now +30 min
action = send email to assign user
(when you create this workflow it will automatically send email whenever this task is create)
this is not what i want

so i have spending some time to think about it and go through database and do trial and error

please check this
module = task, field= due date , operator = equal too , type = value, select date
when you pick the date lets say today, it will automatically fill the field like this for example (05/09/2017)

no time is shown on that field (it means only date is shown
that’s why when you put this logic
due date <= now +30 min, of course it will auto trigger right away to send email
because the system only check for date not the time

the problem that i suspect is on workflow edit parameter which is due date
the logic should be like this

due date <= today
AND
due time <=now +30 min

action send email to assign user on related field

however there’s no option for due time (it should be the option is appear)

is there a way i can add due time to field in task module ?

Thank you