Hello,
Please find at wiki page http://wiki.scn.sap.com/wiki/display/SAPITSM/Multilevel+Categorization
For incidents, the application Service Request / Incident should be used. A categorization schema for change requests has to be assigned to the application Service Order. The parameterTransaction type / Catalog Category is used for both scenarios, Incident Management and Change Request Management. The Value column contains a combination of a business transaction and catalog category, based on the settings from the Customizing activity Assign Transaction Types to Catalog Categories.
After configuration make sure to activate cat. schema at the right date and time.
BR,
K.
