The backshell of the P7 connector could not be found, so Jason-Aerotronics sent me another. He also sent me another antenna for the Garmin 496 GPS, which was also misplaced. The antenna came from a Garmin 430, which are getting swapped out by Aerotronics for customers upgrading. The antenna was free of charge.
The wires for the pilot stick grip going into the P7 were inserted and the connector was assembled.