but aye there will be many other work-around choices for achieving your goal - always is apparently 
Me, I'd use a pop up options window at least then there's a lot more control, otherwise you'd need to use a way system to lock the character in a location, without it the character will just move to the left top corner, set the dialog on the first part so it disappears in micro seconds and live with the options in one place
https://dl.dropbox.com/s/wejy2hysf25pipf/demo%20door.rar?dl=1
Anyway, I was able to show up the black interface on my standard Q/A dialogue but it's cut off from the screen!
EDIT - Resolved. I am waiting anyway for AFRLme reply
I cut out your door & created a open version too ... created an interface but it only works for this atm you could add infinite amount of animation images to the text thing on interface & say which is shown via a condition or value - same goes for what the yes/no buttons do.
to center your interface you have to use absolute positioning & work out half width of resolution - half width of interface image same for height.
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