Interior Cabin Painting

Hello:I have never painted anything for FS2002 but I am willing to learn. I would like to re-paint the interior textures for the "Ready For Pushback 747" but I am having some problems. Below is the procedure I follow, please let me know what I am doing wrong. I'm currently using Photoshop 7.1) I back up the original texture file2) I open the texture file using ImageTool3) I re-save the texture file as a .tga4) Using PS7, I open the .tga texture file and begin to edit5) Finished editing, I re-save the texture file as a .tga6) Using ImageTool, I open the edited .tga texture file and re-save it as a .bmp file.7) Load aircraft in FS2002, but the edited texture file and all of its contents are blanked out "grey".I know I'm doing something wrong here, can anyone help me? I am a novice at this and don't know what I'm really doing. I would like to learn how to re-paint the interior cabins of FS2002 aircraft.Regards,Faustops- The "Ready For Pushback" paintkit didn't contain these interior texture files. The designer instructed me to use the existing texture files found in my RFP 747 folder.