Wouldn't it be nice if one could define custom plantuml-rendering for any resource within Eclipse?
The Plantuml Eclipse-Plugin provides extension point="net.sourceforge.plantuml.eclipse.diagramTextProvider". Contributions to this extension point must implement net.sourceforge.plantuml.eclipse.utils.DiagramTextProvider. Unless the according package is not exported, I cannot contribute my own renderer.
I suggest to add Export-Package: net.sourceforge.plantuml.eclipse.utils to the manifest.