In distance learning, receiving feedback is critical not only for students but also for teachers — from students. However, there is a lack of empirically validated recommendations for designing visualizations of process-oriented feedback for distance learning teachers. In this work, we propose design requirements and visual encodings for process-oriented feedback, obtained through an iterative design-based method involving intense participation of teachers from online vocational courses. Our results show that i) the prototypes built according to the proposed requirements were perceived as useful by teachers and ii) granularity level control, context, data pre-processing transparency, and correlation of process data to outcome data are essential for a successful visual learning analytics system in the studied domain.