just checked - avi's web site says the dac in the speakers is 24/192, so you are ready to go! Get on hdtracks site, browse to 'best sellers', pick an album or two to your taste, pay with paypal if you are not in US, download (they are a bit slow), convert and hit 'play'.
Edit: according to avi web-ste they (Edit: 9T model at least) can do 24/96 from optical. so, (edit) likely, you are ready to go. 24/96 is fantastic quality and you do not need to worry about 24/192 if you cannot play it. 24/96 is almost as good as it gets and there is very little practical difference in stepping up to 192, especially knowing that there is hardly any content available at this sample rate.