Backbone app secured using .NET MVC

I have a single page application using Backbone and a node.js express server.

My partner has written a little authentication page in .NET MVC.

We would like to combine these two components together, which presents various difficulties.

It would be amazing if it were possible to secure the node.js server using the .NET authentication. But I don't know if this is possible. But maybe you can run the node.js server on some, port, say 8888, and then once someone is authenticated with .NET, reroute some of their requests to port 8888.

Trying to recreate the node.js server in .NET presents other problems:

First, the node.js server that I use returns index.html for every request that doesn't have a file extension -- if you hit www.blah.com/foo , it returns index.html, but if you hit www.blah.com/foo.js, it will return foo.js.

Also, .NET keeps secure files a few levels deep in its file structure, but the paths I use in my Backbone application all assume that index.html is in the root of the server. Is there any way to reset or adjust the root of the .NET server depending on the route you request?

Unfortunately, writing the authentication system in node.js is not an option.

Thanks :)