How to add element template to custom bower bundle?

I have created custom bower bundle using bpmn-js library , everything is working great except element template. we added json file as exmaple here but has error Error: unrecognized element <bpmn:ServiceTask>(…) , Any idea how to implement element template with custom bower project , This is kind of road block we been stuck for last three days. I will appreciate if we can get some detail here.


var BpmnViewer = require('bpmn-js/lib/Modeler');
var camundaModdleDescriptor = require('camunda-bpmn-moddle/resources/camunda');
var additionalModules = [
  // 1. require camunda provider instead of the bpmn one (!)
BpmnViewer.prototype._modules = BpmnViewer.prototype._modules.concat(additionalModules);
// 2. include camunda moddle descriptor
BpmnViewer.prototype._moddleExtensions = { camunda: camundaModdleDescriptor }

module.exports = BpmnViewer;