Triadis Engineering Glide Computer and Navigation System Owner's Manual page 14

Having switches on the control stick grip is very useful as it al-
lows the pilot to interact with XCSoar without having to reach for
the instrument panel. It is recommended that at least the message
(Acknowledge and Repeat) switches be on the stick grip.
Custom-made stick grips suitable for gliders are commercially avail-
able. A switch module is available from Triadis Engineering to
connect the switches to Vega. Contact your Altair/Vega dealer for
details.
A large variety of stick grips are available from Aircraft Spruce in
the USA:
http://www.aircraftspruce.com/menus/el/gripspistolstick.
html
A recommended arrangement of the joystick buttons when used
with Vega is presented below.
Arm
Adv
Zoom
in
Ack
Display
Rep
Zoom
out
14