When Iran's president Ahmadinejad made his disgusting revisionist remarks about Holocaust, my first thought was, that this would probably isolate Iran severely. Even Russia had to condemn it, for national and historic reasons: Around 20 million russians died in ww2, some of them as soldiers fighting the German nazi regime. Those russian soldiers were heroes, not only for Russia but for the whole of mankind, because it was a fight against absolute inhumanity - the Holocaust.
As far as I can see, it is more than difficult for any Russian government to cooperate much with a regime, which openly denies Holocaust.
My analyse seems to be confirmed by an article in Mosnews.com