About 2,600-2,800 Soviet prisoners of war were handed over to the Germans in exchange for roughly 2,200 Finnic prisoners of war held by the Germans. In November 2003, the Simon Wiesenthal Center submitted an official request to Finnish President Tarja Halonen for a full-scale investigation by the Finnish authorities of the prisoner exchange. In the subsequent study by Professor Heikki Ylikangas it turned out that about 2,000 of the exchanged prisoners joined the Russian Liberation Army. The rest, mostly army and political officers, , most likely perished in Nazi concentration camps.. What month and year did the Wiesenthal Center submitted an official request?