@Override
public void addExistingModelElements(final EObject eObject, final EReference eReference) {
        if (eReference.getEReferenceType().getInstanceClass().equals(MyRole.class)) {

                final Set<EObject> elements = createRoleObjects();//loads them from DB and creates instances

                ECPControlHelper.removeExistingReferences(eObject, eReference, elements);

                final Set<EObject> addedElements = SelectModelElementWizardFactory.openModelElementSelectionDialog(elements,
                                eReference.isMany());

                ECPControlHelper.addModelElementsInReference(eObject, addedElements, eReference, editingDomain);
        } else {
                super.addExistingModelElements(eObject, eReference);
        }
}

@Override
protected Image getImage(final String path) {
	switch (path) {
		case ICON_ADD_EXISTING:
		case ICON_ADD_NEW:
		case ICON_DELETE:
			return imageRegistryService.getImage(FrameworkUtil.getBundle(MyMultiReferenceSWTRenderer.class), path);
		default:
			return super.getImage(path);
	}
}

@Override
protected boolean showAddNewButton() {
	return false;
}