I want to ensure that I have the details of the situation correct. So you have a form field on your confirm page that holds the formatted date correct? In the store order summary server behavior you are selecting this text field to bind to the date column in your orders table.
Have you checked on the value of the posted form element before it is being inserted to ensure that is contains the date properly formated like you are expecting it? Please post back and include this info, and also if you can please post back with the confirm page minus any of the sensitive details so that we can take a look at get a better idea for how the page is setup.