This paper (1) gives a brief description and explanation about the D-case technique and E-learning system (web portal) called KISSEL (Knowledge Integrated Server System for E-Learning), which was designed especially for the teachers' communities of Elearning in Asian and Pacific countries. (2) To point out our discussion, lessons we've leant and a summary of the end result after the D-Case technique was applied to establish assurance to the "data/usage flow diagram scenario" of the KISSEL system. Applying D-Case to such small systems can still provide valid assurance about how dependable these non-complex systems are.