Our existing installer registers an Outlook-Addin. Technically this add-in consists of several COM objects registered in the system registry plus creating some additional registry entries below HKLM for Outlook to find the add-in.
Is there a way to achieve this when our app is packaged using Cameyo?
No, Outlook 2016 crashes immediately without showing a window when started that way.
And even if that would work, it would require our users to start Outlook using such a command-line instead of the start menu entry they are used to. And furthermore, there are other ways for user's to start Outlook, e.g. by clicking on a mailto: link.
If the natively installed application cannot be launched within the virtualized environment, the packaged add-in will not be recognized outside the virtualized environment. You would have to install it unvirtualized.