Accessing sub-diagram of class method in Doc Composer

In a Class object, I can reference an Activity Diagram and output it in Doc Composer as follows:

<HasSubDiagramChecker diagramType="ActivityDiagram">
  <Text style="@heading+">Implementation</Text>
  <ForEachSubDiagram diagramType="ActivityDiagram" ignoreLastSeparator="false">

I can also link to an Activity Diagram from an Operation within the class, but I can’t access it in Doc Composer. The difference appears to be that, for a Class, the diagram appears in a tab called “Diagrams”, but, for an Operation within a class, the diagram appears in a tab called “References”.

Is there any way to access the Activity Diagram from an Operation?

The diagram attached to operation is in the form of “reference”. You may copy the content of default “General/Sub and Referenced Diagram (General)” template to the operation section of your template for output it.