Setting the base url of an ASP.NET app behind a proxy server

I have the same issue as the poster of this question Running ASP.NET MVC application behind a proxy with different root relative 开发者_如何学Pythonpath

except that I'm running "classic" ASP.NET 4.0 in IIS 7. Basically, the application is deployed to http://machine/MyApp, but it is being accessed through a proxy server as: http://someotherMachine/SomeDirectory/MyApp. So, ASP.NET thinks that /MyApp is the root, but in this case it really isn't. Is there some magical setting of ASP.NET or IIS that I can set telling it, "Hey, by the way the root of this application is actually SomeDirectory not MyApp?"

Can you just create a directory like SomeDirectory on your web server, set that as the root application, and then create a virtual directory under SomeDiretory that points to MyApp?