Empty date Datafields show default values

I have multiple textboxes wich are binded to date datafields. When the datafield is empty the text box has the default value 12:00:00 AM. In K2.Studio the datafield is checked as Empty Date.

To have an empty textbox i have to validade it in codebehind to remove the default value, but i'm dependent of regional settings, because i tested in another server and the default value was 00:00:00.

Does anyone knows how to solve this?
thanks