Don't know if fpsc handles bump maps since it uses normal maps. In the video tuts for the segment editor it explains the naming convention to use. In short this is how its like. It uses a suffix to determine which textures to load.
mytexture_D2.tga - The D2 tells it that this is the bitmap to use when no shader are used.
With shader turned on, fpsc will load these files, if found, based on the root filename.
_D - Diffuse map
_N - Normal map
_S - Specular map
_I - Illumniation map
eg. mytexture_D.tga, mytexture_N.tga, mytexture_S.tga, etc
