void ParseISO8601DateTime(string xsdDate)
  Property Description  
    Argument xsdDate valid XML Schema date  
    Description Populates this XmlDateTime with the value specified as a valid XML ISO8601 date, gDay, gMonth, gYear, gMonthDay or gYearMonth.  
    Remarks A valid dateTime (see ISO 8601 standard) comprising [-]CCYY-MM-DDThh:mm:ss[.ff][[Z]|[[+|-]hh:mm]]
where the parts in [...] are optional.

Throws: LtInvalidValueException thrown on parsing invalid values.
See: ParseISO8601Date(std::string)
See: ParseISO8601Time(std::string)