I've received some feedback that the toolbar button for the Copy to Device addin is not being shown.
I tried this myself and found a couple of cases in which this would happen.
First, my tablet has a 1024x768 screen, which is small by today's standards. There is only room onscreen for a small number of buttons, and I found the button hidden offscreen in one instance. Selecting the command causes the button to appear - office detects that this command was recently used, so moves it on screen.
I've had spotty results with installing my addins via the MSI. I always run setup, and for those that have looked through the project, you can see all the registry keys which need to be created during setup. I noticed this problem while I was creating the addin. I've been trying to track down a consistent "repro" since. For the meantime, I always recommend running the setup.exe.
Hope this helps clear up any errors you may be seeing. As always, let me know if this doesn't work.