How to add 'Test Script Steps' to a 'Test Case - Test Script' RPE report ?

I need to create a Report that lists: Test Case - Associate Test Script(s) - Test Script Step(s).

Because Test Script Steps are not available in RRDI (see this post), I need to use RPE.

The picture below shows exactly what I want to generate, and where I am so far ...

In a nutshell, getting inspiration from this great CLM2012 Report Workshop, I created a RPE report with:
(1) 1 Table having 1 Container which uses the 1 RQM Data Source Schema: feed.xsd.
In this table, I have 1 row per Test Case (feed/entry/content/testcase), column1= Test Case Title, column 2 = Test Case Description.
(2) In column 3, I wanted to display all Test Scripts associated to the 1 Test Case.
For that purpose, I involved a 2nd RQM Data Source Schema: qm.xsd, i.e.:
I used a Container on feed/entry/content/testcase/testscript from feed.xsd.
Within the Container, I used a 'Data Source Configuration' (Target source = qm.xsd, Inherited Data Configuration = feed.xsd), and added another Container using the qm.xsd where I dropped the testscript. The table row cell contains the qm.xsd testscript/tile
(3) I don't know what to do next to display the Test Script Steps of each Test Script in column 4.
Should I involve a 3rd Data Source (e.g. testscript.xsd), or not ... if Y, where, if N, what should I do ? - see ? mark in picture.

Thanks