Does anyone know how to update an XML Schema for use in RPE to access DOORS 9 via DWA when tracing from RQM?

I have a user who has DOORS 9 requirements linked to his RQM test cases and we are trying to generate an RPE template to output his test cases with linked requirements.  The linkages are done via OSLC links to DOORS through DWA.  I have tried to follow the guidance in https://rpeactual.com/2014/12/15/rpe-and-doors-web-access/ to build the template and it sort of works.  My user has two different RQM/DOORS environments.  The template using the sample DWA schema works fine in one of the environments but not in the other.  We think he is using different DOORS attributes in the two environments (I don't personally have visibility into the non-working environment).  I thought I would try updating the sample DWA xml schema to adjust attribute names, but I can't get my updates to show up in RPE so I don't think I am doing it right.   Can anyone point me to documentation that guides you on manually creating a schema for RPE usage with DWA (or other)?

Thanks,

Jamie.