From R2 2014 we introduced new MaskType for RadMaskedEditBox. It is designed to work with DateTime objects and it is not format restricted. With the new MaskType the input string is parsed to valid DateTime object by using a formal grammar algorithm.
You can read more about this parsing logic here The embedded text editor of RadDateTimePicker is RadMaskedEditBox. So if you want to take the advantages from new DateTime parsing logic the only thing that you should to do is to change the MaskType of embedded editor.
Setting the value of RadDateTimePicker
this.radDateTimePicker1.DateTimePickerElement.TextBoxElement.MaskType = MaskType.FreeFormDateTime;
Me.radDateTimePicker1.DateTimePickerElement.TextBoxElement.MaskType = MaskType.FreeFormDateTime