that is the same thing i normally use. was just hoping that there was an ical subscription out there for nsw as there is with a couple of other states. so far no luck in finding one.
i add a calendar to my list, but then it won't allow me to change the name went i make an entry. not sure why.
ie ... calendar 'nsw school holidays' then make an entry except it won't let me use any of those words in the entry and automatically changes the entry to 'new event'.
NSW School Holliday iCal compatible ics files can be downloaded here, one file per season eg Summer, Spring etc.