Add another editable label to an element (CMMN)

Hi Everyone,

I want to add a second label to the CaseFileItem element on top-right, like this:
and I want to have this second label editable on click (as the default one).

I defined a CustomLabelBehaviour and I obtained the result in the picture above in this way:

this.postExecuted([ 'shape.create', 'connection.create' ], 100, function(e) {

    var context = e.context;
    var element = context.shape || context.connection,
        businessObject = element.businessObject;
    var position;
    if(element.type == 'cmmn:CaseFileItem'){
      position = { 
        x: element.x + 50,
        y: element.y - 5

      modeling.createLabel(element, position, {
        id: + '_label2',
        hidden: !getName(element) && !isStandardEventVisible(businessObject),
        businessObject: businessObject

I specified “_label2” in the definition of ID for not getting the error of having two elements with the same ID.

My problem is that the two labels seem to be a unique object: when I edit the text of one label, both of them are modified.
My goal is to have this second editable label and to put its value in a new attribute in the XML tag cmmn:CaseFileItemDefinition.

What should be the right approach? Thanks.