I have done this just fine. I have been successful in mounting them both directly across from the instance inside, as well as slightly further back on the left (with the bar/counter set right in front of it).
The soda barrels are a little bit picky to place but you can do it. In fact, you can end up moving them out away from the wall..and see through them from behind. I think they could certainly be easier to place, for sure.
