I switched to using the SubmitIncidentAdvancedComponent and was able to map the Primary Contact. It was a bit tricky to get the mappings right but it is now working. As a side note, I've been posting on another thread about issues with SD.RoutingRules, well I really had to switch to the AdvancedComponent because I was able for the usage of the rules, at least in custom forms, by using the DetermineAssignmentComponent as well.