There's nothing to fix or update. To support Seated Passengers, we need to patch the exterior model .XML, and this file is not accessible on airplanes bought on the Marketplace, because it's encrypted.
The only possible way we could ever be able to do that on such airplanes, is if Microsoft would eventually add an "Attach API" (which exists in P3D), that allowed to programmatically attach any object to any part of the airplane, removing the need to modify the airplane files.