     _.each hiddenQueryParams, (param) ->
       _.set requestParams.qs, param.name, param.value
 
-    requestParams.headers = _.extend {}, requestParams.headers, headerParams
+    requestParams.headers = _.extend {}, requestParams.headers, headerParams, defaultHeaderParams
 
     strategyMethod = @getStrategy config.oauth?.tokenMethod
     strategyParams = strategyMethod config, _.cloneDeep(requestParams)

    hiddenBodyParams  = _.filter config.hiddenParams, style: 'body'
    hiddenQueryParams = _.filter config.hiddenParams, style: 'query'

    urlParams = _.extend {}, config.defaultParams, config.urlParams
    headerParams = _.cloneDeep config.headerParams
    bodyParams = {}
    uri = @_replaceParams config.url, urlParams


    return path

  _generateHeaderParams: (defaultParams) =>
     params = _.filter defaultParams, style: 'header'
     headers = {}
     _.forEach params, (header) ->
       headers[header.name] = header.value

  onEnvelope: ({config, message}) =>
    message = _.cloneDeep config unless message?.url?
    @buildRequestParameters message
