Ask first..
Hey,
I agree with the above.... You would have to check with the mountain or be prepared to do some night hiking from your accommodation!! Australia isn't as open to new ideas as what you see in the US, people also have snow in their local parks to go rip over there. One of the new MTB videos has a snow session in it, a couple of the pros with their normal DH rigs in a groomed resort.(seasons..?) It did look closed though...! I'm guessing it would be fun to do once but it would be like getting an F1 race car and driving it on the dirt!! If you ski.... you should also know to try not to 'lean' in turns.... this thing would be all lean!!!! =( Also, if you're a bit crafty.... a couple of blocks of wood/pvc/aluminum/etc, a few saddle clamps and a couple of old axles could achieve the same result for a trial run..... we used to trial new things on STAFF day where I used to work.
good luck...