Запустите программу инсталяции и она вставит текстуру в Вашу папку B738.
Затем откройте с помощью блокнота файл aircraft.cfg который находится вот по этому адрессу:
C:\Program Files\Microsoft Games\Microsoft Flight Simulator X\SimObjects\Airplanes\B737_800
и перед строкой [General] вставьте строчки приведённые ниже.Вместо ххх поставьте порядковый номер вашей текстуры

пример вот здесь:http://img211.imageshack.us/img211/6614/xxxrj6.jpg


[fltsim.xxx]
title=Boeing 737-800 RST Airlines
sim=Boeing737-800
model=
panel=
sound=
texture=rst_air
kb_checklists=Boeing737-800_check
kb_reference=Boeing737-800_ref
atc_id=VP-RST
atc_airline=RussianSkyTeam
atc_flight_number=ST364
ui_manufacturer="Boeing"
ui_type="737-800"
ui_variation="RST Arlines"
ui_typerole="Commercial Airliner"
ui_createdby="Microsoft Corporation"
description="One should hardly be surprised that the world's most prolific manufacturer of commercial aircraft is also the producer of the world's most popular jetliner. The 737 became the best-selling commercial jetliner worldwide when orders for it hit 1,831 in June 1987 (surpassing Boeing's own 727 as the previous champ). However, it wasn't always that way\s in the first few years of production, there were so few orders that Boeing considered canceling the program. They didn't, and the airplane has more than proven itself in over three decades of service."

