Here is a document created on the occasion of a 2001 exhibition in Graz, Styria, Austria to mark the 150th year of the voayage of the Novara.http://www.uni-graz.at/ausstellungen-2001-kriegsmarine.pdf
about the Austrian Novarra expedition to Australia and New Zealand. It is all in German but if you scroll down to page 6 there at the bottom is a picture of Wiremu Toetoe Tumohe and where your ancestor is mentioned.
Page 14 has some pictures of landmarks.
On page 19 it states that during a later expedition in 1885 the ship's commander asked the Maori king if he could meet the two Maori who had been in Vienna but "despite king Tawhiao personally trying to arrange the meet, he was not able to meet them".
The passage above the handwritten account is a translation of that. Here it states:
"We made a trip to the country's hinterland. First by rail to Te Avam the last railway station before the border to the King Country. There we took a car to Kiki and spent the night at Major Jackson's house. The next day we visited the battle scenes of the last Maori war and met the headman of the Manukiri tribe Tamatin (who was the father in law of Kig Tawhiao. From there we continued on to the Maori village Watiwatihow, via Alexandra, where wee met several tribal leaders including the king's son. The sailor who travelled back to Vienna with the Novara currently has the position of minor tribal leader, he is called Te Hemera. I was not able to speak to him although he had been notified of our coming by telegraph by a tribal leader."
Page 21 has photos of King Tawhiao and his wife.
Hope you enjoy the report, it is truly amazing. Maybe I can find some more things, including newspaper reports.