The original poster wants to fly INTO Russia and return FROM Germany. This is a OPEN JAW, and not a stopover. This is perfectly legal. By the way, they are pretty liberal on the open jaw thing.

We did Nashville to NY and Nassau, Bahamas to Nashville on the return. (we traveled by ship between NY and Nassau). And before you ask, we booked the trip, not the cruiseline, using an award. And, we got the exact dates we wanted only 6 weeks before the trip.