void SetGDay(byte day);
  Property Description  
    Argument day day sets the Day part of the date. (Valid Range = 1 to days in month)  
    Description Populates this CDateTime as type gDay  
    Remarks Throws: LtInvalidValueException thrown on parsing invalid values.
Throws: LtInvalidStateException thrown if this DateTimes current type is not either zeroYear or gDay.