Ed - I just opened my Kamber 22 and initially had the same reaction as you regarding vertical vs. diagonal ski carry. I then realized that if you take that top strap out and direct the buckle-side of the strap through the narrow loop/tunnel (don't know what else to call it) that sits between where the strap starts and the other buckle, it creates a loop for your skis at the top right of the pack. Doing with this will give you diagonal carry. Osprey does a poor job of demonstrating this as I have not seen any solid how-tos.
Tom from Denver