.desktop files for app-in-snap

[Vasilisc]

Please help me. If I launch the program in the Terminal - well done, but 
I can't start program from Unity Launcher.

I tried to change parameter Exec in ~/.local/share/applications/app.desktop
Exec=app-name
Exec=snap-name.app-name
Exec=$SNAP/usr/bin/start-script.sh
Exec=$snap.$app (http://snapcraft.io/docs/snaps/structure)

and studied case 
https://github.com/ubuntu/snappy-playpen/blob/master/vlc/setup/gui/vlc.desktop
but it didn't help.

-- 
Best regards,
vasilisc