Command cmd = new RecordingCommand(domain) {
  protected void doExecute() {
    //owner is a Component
    Comment comment = owner.createOwnedComment();
    //edits the comment, e.g. apply stereotype to it
    //creates the view:
   ViewDescriptor viewDescriptor = new ViewDescriptor(
                new EObjectAdapter(comment), Node.class,
                                ((IHintedType) org.eclipse.papyrus.diagram.composite.providers.UMLElementTypes
                                        .getElementType(CommentEditPart.VISUAL_ID)).getSemanticHint(),
                                diagEpart.getDiagramPreferencesHint());

   viewDescriptor.setPersisted(true);

   CreateViewRequest req = new CreateViewRequest(viewDescriptor);
		
   Command comm = ownerPart.getCommand(req);
   comm.execute();
   
  }
}

domain.getCommandStack().execute(cmd);