How to export a DM diagram with RPE

Hello! I'm trying to use RPE to export diagrams from DM but i can't find how to define my REST data source and how to fill its URI to export a specific diagram.

I've already looked at several examples, especially Kevin Cornell's DM Reporting Tutorial, but it seems that my DM data model is different, maybe because my definitions and diagrams were not created directly in DM but were created in System Architect software and then were imported in DM.
When i want to define my diagram data source by REST discovery wizard, i first have these main domains : bpmn, collaboration, deploy, dmcore, notation, projects, uml, umlProfile. I don't know in which one i have to look for and what to look for.
I tried with "uml/UMLDiagram" but then i'm not sure how to configure the URI of my data source. I tried for example with URI = "https://......../dm/models/18270" but this generate a connexion failure.

Anybody can give me a beginning of solution ?
Thanks!