Personally, as well as asking a few questions about the ITOM applications themselves, I look for the domain kowledge - what kind of infrastructure experience does the person have, knowledge of monitoring etc. To really do things like Service Mapping well, you kind of need to understand how these systems hang together. Good luck with your interview! In terms of configuring ITOM products, definitely expect some MID server questions and have a good understanding of how network topologies might affect your MID placement and scheduling of discovery jobs
