How to use AngularJS ng.resource.IResource with TypeScript.

app.ts

/// <reference path="angular.d.ts" />
/// <reference path="angular-resource.d.ts" />

interface IEmployee extends ng.resource.IResource<IEmployee>
{
    id: number;
    firstName : string;
    lastName : string;
}
interface IEmployeeResource extends ng.resource.IResourceClass<IEmployee>
{
    update(IEmployee) : IEmployee;
}

angular
    .module('myapp', ['ngResource'])
    .factory('EmployeeResource', ['$resource', ($resource : ng.resource.IResourceService) : IEmployeeResource => {

        // Define your custom actions here as IActionDescriptor
        var updateAction : ng.resource.IActionDescriptor = {
            method: 'PUT',
            isArray: false
        };

        // Return the resource, include your custom actions
        return <IEmployeeResource> $resource('/api/employee/:id', { id: '@id' }, {
            update: updateAction
        });

    }])
    .controller('TestCtrl', ['EmployeeResource', (Employee : IEmployeeResource) =>
    {
        // Get all employees
        var employees : Array<IEmployee> = Employee.query();

        // Get specific employee, and change their last name
        var employee : IEmployee = Employee.get({ id: 123 });
        employee.lastName = 'Smith';
        employee.$save();

        // Custom action
        var updatedEmployee : IEmployee = Employee.update({ id: 100, firstName: "John" });
    }]);

i made a customize version of ngResource, which i transform result after they become ready, the original function transformResponse change and destroy type of data, so i intruduce a new function called transformResult, but how should i introduce this callback/config to the TS ?