For daylight simulations, there’s no such thing as a Wall. They are all shading surfaces. For your analysis, assign the shading geometry as HBsurface and assign the radiance properties. Make sure to also supply these HBsurface to the HBobjects input on the daylight simulation component. Run an image based analysis first to see that everything is being written to Radiance right. Then you should proceed with the rest of the studies.