Turn on away mode on alarm system when door is open

I have a home alarm system with a door contact sensor on the front door.
When i turn on the away mode i have a 15 second delay time before the alarm goes of.
When i leave the house the door is usually already open because other people already left and are waiting for me.
Now i have to close the door because otherwise i cant activate the away mode via the touchpad.
How should i set my settings so i can turn on away mode while the door is open?
of course i close the door before the 15 second delay time is ending.

I have the same problem. Can we have any feedback or support for delay time which should manage this case?
thank you