Unable to add the EFF attributes to the Standard sales order XML and display data in report.

We are trying to modify the standard Sales Order report template to include Extensible Flexfield (EFF) attributes. The standard report uses a Sales Order XML data file from the seeded data model. We have attempted multiple scenarios by manually adding EFF attributes to the XML, but the EFF data is not appearing in the report output.

We need guidance on how to properly include Sales Order EFFs (both header-level and/or line-level, as applicable) in the data model so they can be retrieved and displayed in the BI Publisher report template. A sample XML file has been attached for reference.