I has returned, you can do it much easier. Find the folder as I has returned described.
Now rename the crosshair.dds file to something like original_crosshair.dds. That's just in case you're going to need it again.
No goto you're photo-editing application what ever you use. Start a new image with size 64x64 pixels and a black (RGB 0,0,0) background. Draw your crosshair and save it in the folder where you just renamed the crosshair.dds file. Save it using Truevision Targa file format (.tga) in thgat folder with the name crosshair.tga.
Now start your level in FPSC and the engine intself will convert the crosshair.tga to a .dds file.
No need for converters, FPSC has one build in, but it seems like most people overlook that. Just make sure you always remove or rename the original .dds file and name you .tga with the same name as the original .dds file.
This way you can edit texts, huds, buttons and even textures also using the .tga format.
