activiti rest call

$http({ headers : { 'Authorization' : "Basic " + $scope.auth, 'Content-Type' : 'application/json' },
                                method : "POST",
                                url : $scope.config.baseurl + ':' + $scope.config.port + '/' + $scope.config.suffix + '/service/runtime/process-instances',
                                data : { "processDefinitionId" : "proceso:21:102548",
                                         "variables" : [{
                                               "name" : "titulo",
                                               "value" : title
                                         },
                                         {  "name" : "msg",
                                            "value" : msg ,
                                            "scope" : "local"
                                         },
                                         { "name" : "user_email",
                                           "value" : getUserMail($scope.user)
                                         }]
                                }

                        })