How to access RSA BPMN diagrams on DM 4.0 using Rational Publishing Engine?

I try to create a simple report that should contain all BPMN diagrams from a DM-managed RSA BPMN model.
Following this Tutorial (version 2.0 for DM 4):
https://jazz.net/wiki/bin/view/Main/DMReportTutorial
, I use the REST Schema discovery feature, e.g. on

https://myserver/dm/reporting/uml?project=MyProject [...]

It is quite easy to find the diagrams for the UML domain:

$uml/PackageList/Package/diagrams/UMLDiagram/image

However, I can't find diagrams inside a bpmn domain model at

https://myserver/dm/reporting/bpmn?project=MyProject [...]

There is a separate "notation" domain, which contains diagram elements. But I don't know how to use it as a data source for the RPE template.

Does anybody know how to access the BPMN diagrams using the REST services?

Thanks for any hints
  Florian


btw: Schema discovery only works in RPE 1.1.2.2 - NOT latest RPE 1.2. release - seems to be a regression to the patches mentioned in the tutorial.