How configure SED props.conf on a Heavy Forwarder to make a field CIM compliant?

All, My first time messing with data manipulation at the heavy forwarder tier. Specifically looking to CIM a field my developers can't fix at code. Essentially quick sub elapsedTime to duration. Version: Splunk 6.32/UF 6.24 Linux CentOS 6.x props.conf [log4j] SED-alter = y/elapsedTime/duration/