Alpha C-141B Freeware in FSX?

Does anyone know why the Alpha C-141B model will not display in FSX. There is an error that the model cannot be displayed. The Alpha C-141A works OK. I used a hex editor and both models are for FS2002/FS2004 according to the first line (MDL8MDLH). The date on the model file for the B version is earlier than the A version. The B model has two model versions (ramp and no ramp). Neither will display in FSX. Can I just copy the A model over into the B folder and rename it properly for the B version? Since there is only one A version model there probably is no way to display the no ramp version. Thanks, best regards, Bob.