Render files under generated doc-files in javadoc

I want to include some class diagrams in the javadoc of my packages (`package-info.java`) and in my classes ('*.java`).

I do that at maven level by having a `src/main/plantuml` with a bunch of `doc-files` folders mirroring the sources tree, and using one of the `plantuml-maven-plugin` configured to generate from each `*.puml` file a corresponding `*.png` image in `target/generated-sources/plantuml`.  At maven level, it works well : the plugin picks-up the `*.puml` files during the `generate-sources` phase, and javadoc picks the generated `*.png` files when generating the `*.html` doc.

IntelliJ doesn't seem to support that. I have added the `target/generated-sources/plantuml` folder in the project structure as a source tree. `target` is a globally excluded folder, but as `target/generated-sources/plantuml` is added, it is properly listed as a source folder.

I tried both to generate the `*.png` files externally by first running maven and internally using Maven → Generate Sources and Update Folders but to no avail. I have checked the `*.png` files are present in the `target/generated-sources/plantuml` folder.

Is it possible to have Intellij render these images in the editor?