function SOF_flatDateChanged(calendar) {
	// Beware that this function is called even if the end-user only
	// changed the month/year.  In order to determine if a date was
	// clicked you can use the dateClicked property of the calendar:
	var p 				= calendar.params;
	if (calendar.dateClicked) {
	  // date
		var sHiddenFieldId 	= '';
		var fldHidden 		= false;

		sHiddenFieldId 	= p.inputField.id.replace(/__flat$/, '');
		fldHidden 		= document.getElementById(sHiddenFieldId);
		if(fldHidden){
		fldHidden.value = calendar.date.print('%Y-%m-%d %H:%M:%S');}
	}
  };