add web api route to exists web site cannot modify global asax - asp.net

Question

I have a web api project and i can run it locally, but when i publish dll´s to bin folder in the web site, is not taking the route config. I.ve been unable to modify or replace the global asax becasue it has its own implementation. where is the best place to set mi web api route config, how can i do it with an httpmodule?
public class WebApiApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
}
}
UPDATE:
i added a httpmodule, and is not mapping the route, is sending http 404:
public void Init(HttpApplication context) {
try
{
AreaRegistration.RegisterAllAreas();
var routes = RouteTable.Routes;
// Controllers with Actions
// To handle routes like '/api/controller/route'
routes.MapHttpRoute(
name: "ControllerActionAndId",
routeTemplate: "api/{controller}/{action}/{id}",
defaults: new { id = RouteParameter.Optional },
constraints: new { id = #"^\d+$" }
);
// Controllers with Actions
// To handle routes like '/api/controller/route'
routes.MapHttpRoute(
name: "ControllerAndAction",
routeTemplate: "api/{controller}/{action}"
);
// Controller with ID
// To handle routes like '/api/controller/1'
routes.MapHttpRoute(
name: "ControllerAndId",
routeTemplate: "api/{controller}/{id}",
defaults: null,
constraints: new { id = #"^\d+$" } // Only integers
);
// Controller Only
// To handle routes like '/api/controller'
routes.MapHttpRoute(
name: "ControllerOnly",
routeTemplate: "api/{controller}"
);
}
catch { }
}

Answer 1

can you change the webconfig if you can't change the global assax?
with a httpmodule you would get somthing like
<system.webserver>
<modules>
<add name="WebApiStartModule" type="myproject.WebApiStartModule, assembly"/>
</modules>
<system.webserver>
public class WebApiStartModule : IHttpModule
{
public void Init(HttpApplicationContext) {
var routes = RouteTable.Routes
routes.Clear()
//initialize routing here
}
}