French to English Bus/Financial Business/Commerce (general) Document with clarification of SAP standards

A business speaks about its OTP (WBS-Work Breakdown Structure) but also its éOTP. It would appear to be a sub unit of the OTP, but is it possible to say eWBS, or should I use "sub-WBS"?
The terms are used throughout the long document. I can't find anything in the SAP library to help. They talk about sub trees, but I think this is a more general concept.