>I do not know if this is possible. But, as I cannot deploy a fix in the production environment, I would like to put temporarily in the global.asax file some Application_Start() code. So far so good, but, the framework also has an Application_Start() code that is executed as global.asax is inheriting from my base class. So, is this possible to have code in that event at both locations?

I don't think it's possible. Application_Start() code in the asax.cs will take precedence over any Application_Start() in the .asax markup file.
You can hook up to HttpApplication events that *aren't* handled in code behind - but I don't think that's much help :-{