Well that is easy to adapt then. You just need to buy some strips of wood 15 to 25 mm thick, and cut them 50 cm long and ([44-36]/2= 4) 4 cm wide. Paint them with good quality exterior paint, and fix them to the top of the Italian box, leaving you with a top centered gap of 36 x 50 to put your flow box onto. Here is a photo of the French version, which has a slightly smaller gap:
@Michael_Bush has also adapted 10 frame to 8 frame boxes very simply with a strip of wood only on one side. I think the French solution is more elegant, but the point is, the bees don’t care about the “step” in the walls. It works just fine. 
When your Italian box is full of bees, I would put the Flow brood box on top, with the wood strip “adapters” and let them fill the frames in that. When that is bursting with bees, put the Flow super on top. That may not be until next year, but at least you should be able to get the second brood box started this season. 