PITCH Alt/Off/Att binding is missing for 3pos switch (TM WH for example) even though there is one for ROLL AP. To fix this, here is the missing lines.
{ down = control_commands.ApPitchAtt_EXT, up = control_commands.ApPitchAlt_EXT, cockpit_device_id = devices.CONTROL_INTERFACE, value_down = -1.0, value_up = -1.0, name = _('Autopilot PITCH Switch - ATT HOLD/A/P OFF'), category = {_('Special For Joystick'), _('Instrument Panel'), _('FLCS')}},
{ down = control_commands.ApPitchAlt_EXT, up = control_commands.ApPitchAlt_EXT, cockpit_device_id = devices.CONTROL_INTERFACE, value_down = 1.0, value_up = -1.0, name = _('Autopilot PITCH Switch - ALT HOLD/A/P OFF'), category = {_('Special For Joystick'), _('Instrument Panel'), _('FLCS')}},
This works but it will mess with the switch solenoid and A/P don't disconnect when it supposed to and might cause suboptimal flight characteristics.