It has to do with the way poser sees the object and whether the object has a materialed inside. Or something like that. It is for this reason I do the contruction kits. Having had a difficult time setting up cameras and lights with many of the fully built sets. About the best I could say to you would be to set the biulding where you want it in relation to where the ppl will be and set the lights to spots and put them all at 0/0/0 x/y/z and them point them wher youlike them do some test shots to see if you have the set in the right spot. Then add it to your prop library (My folder is called working) then remove the model add and pose and light the ppl. then bring the saved prop back in. At least that is how i do it with fully built props.