Sharing App_Code and master pages with nested ASP.NET applications

Is it possible to share the App_Code directory and master pages with a nested application? I have a third-party newsletter application installed in my web app and I want it to share the same look and feel as the "parent" application. When I try, though, I get an error saying that the child application can't reference any of the exterior files.

I've done quite a bit of se开发者_高级运维arching and found a lot of pages on overriding the Web.config in a child application, but I haven't been able to find anything that quite fits my situation.

The web server is running .NET 2.0 with IIS 5.0.

I have never tried this, but it might be possible to access the master page of the "outer" application by implementing a VirtualPathProvider in the nested application.