You can't add to the PocketFMS data directly on SkyView, but there are two options here:
1) If there is an aeronautical feature like an airport or obstacle that is missing, you can contact the PocketFMS team directly to have them review adding it. See
this page for more details.
2) If you just want to add your own user waypoints, SkyView has a pretty robust user waypoints editor and manager. Your best bet for learning about that is to read about creating and working with user waypoints in chapter 7 of the SkyView Pilot's User Guide, which you can download from http://docs.dynonavionics.com.