The management server is aware of scenarios only for external users (users of the customer-facing website). You configure the scenarioManager.xml file to have one Process Editor Server, which is an Service Center instance:

<?xml version="1.0" encoding="ISO-8859-1" ?>
<process-manager-configuration>
 <process-editor-server>
  <server-name>ATG CSC_Host: 8851</server-name>
 </process-editor-server>
</process-manager-configuration>