Does it matter? You can still play the Russians, Allied with the British invading the Pont Du Hoc or lead the American charge at Stalingrad... where's the sodding historical realism there? Its about entertainment...the Finns were in the war, they fought along side the Germans against the Soviets... what more do you need? The campaign is where history matters and that where we keep it.
Also, there's no real timeframe for the this mod, as far as I'm concerned, it takes place all over.