Changing AI Textures

I downloaded the Southwest Airlines Flightplan package(ver3.9) There are way to many Shamu Ones displayed. I think I've seen one 737 with the old paint scheme. I also downloaded the textures for the new Blue paint scheme, However. When I install the the textures the model no longer appears in FS. I changed the Aircraft.cfg to reflect the changes and the aircraft are no where to be seen.
Any ideas or suggestions would be appreciated on how to get the blue textures to work.
Any ideas or suggestions would be appreciated on how to get the blue textures to work.