Re: "...Am I missing something? If you don't 'pull' when you select VS, nothing will happen and 45 seconds later the VS will disappear?..."
Sorry about the late reply. As soon as you wind up the altitude to above your current altitude the descent mode changes from Open Des to V/S, so all you should need to do is adjust the selected V/S by turning.
As for full flap and SB: don't know!