There is a way but it requires 3d studio max. I know you are using blender.
you will need max tool 2.0 (search the forums for it). It will only import ship meshes. Roids, planets, and structures get errors. It can export as well, but not near as good as just using XSI. 3dsmax can not simulate XSI's tangent system which is required for the models shaders to work right in sins.
You can make your model in any modeling program you wish, but it needs to be finalized in XSI (textures, tangents, and hardpoints).
