Reporting service Application Startup

I am working on an Authorization Extension for Sql Reporting services 2012. I need to register my IOC container at start up of the ReportService. The global.asax inherits Microsoft.ReportingServices.WebServer.Global and has no code behind.

Do I need to create a global.asax.cs with an Application_Start method? Can this inherit System.Web.HttpApplication?

or Can I extend Microsoft.ReportingServices.WebServer.Global? If so, in what .dll can this be found to reference?

Or is there another approach to take to hook into the reporting service app start?

Thanks for any help,

Bill