[IMP-users] Is the hydration layer not used outside of fitting?

I'm attempting to generate purely a theoretical saxs profile with no fitting. I noticed in the output and in the manual, it doesn't appear that the hydration layer is taken into account in FOXS when it comes to no fitting. The only options are to set ranges, but again, these are only used for fitting. I'm looking for something similar to crysol where you can indicate the solvent density exactly even without fitting.