you could try this:
export the model to a 3d program, convert to .x, and place here entitybankuser (must be the only .x file in "user")
open entity maker (official fpsc website, under files)
change all the settings you want, but leave the texture line blank, and make it DYNAMIC
copy all the texture files to user
open your model's .fpe file with notepad
change the line "materialindex", put in whatever number textures there are.
put in fpsc, and test
OR, use sketchup to export to a .obj file, uv map it with UVMAPPER (google it), and use entity maker, only his time choosing the texture in the texture line.
Call me Alex. Please. OR at least let me change my forum name...