I don't think it's possible at the moment since the entire game is paused when dialog options are displayed.
So you may have to wait until this behaviour is changed or your request is implemented: http://www.adventuregamestudio.co.uk/tracker.php?action=detail&id=44
Edit:
Found old thread: http://www.adventuregamestudio.co.uk/yabb/index.php?topic=17047.0
So you may have to wait until this behaviour is changed or your request is implemented: http://www.adventuregamestudio.co.uk/tracker.php?action=detail&id=44
Edit:
Found old thread: http://www.adventuregamestudio.co.uk/yabb/index.php?topic=17047.0