Hey Victor,
You should Define Change Request Steps for Rule-Based Workflow
then use them in your decision tables to configure the workflow... that should do it.
Please refer to this document: http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/1083c36f-a765-3110-f8a5-d03be6b06d0e?QuickLink=index&overridelayout=true&59017145669652
Cheers,
Boris