Hello Tim,
Basically you have two options:
1) Create a SAP event watcher mapping a SAP event to a CPS event and make your job start when the event is raised. To setup a SAP event watcher create an Event Rule in your SAP System object. After this you have to run the SAP_SynchronizeEventCriteria job to move the rules to SAP. The only requirement for this is that XBP3.0 is available in your target SAP System.
2) Add parameters STARTCOND_EVENTID and STARTCOND_EVENTPARM to your SAP job. This will start the job on the SAP side, but in there it will start waiting for the defined event in SAP.
Regards Gerben