Flight Simulator X Installation problem?

I was recently trying to install a freeware F-117 that I downloaded, and I made sure I put the gauges in the gauges file, the plane in the SimObjects>Airplanes File, and such, but when I go to aircraft selection, it doesn't show up. It's worked with other freewares, like F-16's, F-22's, F-35's, F-25's, B-2's, SR-71's, 747 (Thai Airlines), Black Hawk, etc, etc....but not for this one or for multiple others including E-3's, E-2's, and U-2's..please help..this would solve so much for me.