The court in the western city of Feldkirch sentenced one of the defendants - a 24-year-old - to nine years in prison, and the other, aged 21, to eight years. Police described the two as skinheads, but did not identify them by name.
The victim - a 20-year-old German national, according to broadcaster ORF - had been sleeping on a bench in the neighboring German town of Lindau one morning in August 2006 when the two defendants came upon him and started their assault. The victim was in a coma for weeks.
Before the verdict was announced, the men confessed to the crime, apologized to the man's relatives and said they wanted to start a new life, ORF reported.
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969