Crossing Belarus with Russian visa (Minsk)

Hello Everybody,
I want to go from Moscow through Belarus to Poland with my German car with German plates. I just found out that the Belarus/Russian boarder does not exist anymore and that my temporary RU custom papers (vremnie voz) wil be accepted by the Belarus customs and I can get even new ones from them valid as well in Russia upon my return trip to Moscow. THe question is whether they will make problems when I get to the Belarus/Polish boarder (coming from Moscow) if I do not have a Belarus (transit) visa. any experience or number of a contact person?
By the way, if the temporary import issue interests you read my thread here: Protected content
Cheers from Moscow
Matthias