In V5 the solid infill option is just rectilinear with no options to change the solid infill direction. I use complex infills on certain parts for directional strength and the lack of ability to set the infill and solid infill directions/layup really compromises V5 for me. Unless I am missing how to do it?
I believe you can go to Edit Process Settings > Infill tab, and change the "External pattern rotation" angle if you want to set the angle of the solid layer fill.