Austrian Gas Vans Trial

In October 1970, former gas van driver Josef W was tried in Austria, and gave this testimony regarding the gassing of Viennese Jews at Maly Trostinets on 14th September 1942:

I heard also that Jews from the Reich were coming and would be gassed...Resistance would have been useless, so I didn't offer any. I loaded these people in and drove to the pit. I had seen that the van was nearly full, that about fifty people were inside...The van ran on idle while gassing. It really should have been run with the choke, so that the gas mixture would be richer, and the people inside would die more quickly. But the choke didn't work in my van. I then drove back...[and] received orders to bring all the luggage to Trostinets. On the day I was on assignment there, 600 people were gassed. [Patricia Heberer, 'Justice in Austrian Courts?' in Heberer and Matthaeus (eds), Atrocities On Trial, University of Nebraska Press, 2008, p.237, citing Strafsache gegen Josef W., Band IX, ON 117, testimony of Josef W., p.16.]

Were Austrians in on the hoax too, in 1970?