Set Default Start Document - asp.net

Question

This seems pretty simple, but for the life of me I can't figure it out.
Using ASP.NET Classic (ie non-MVC), say I have a website www.foo.com that has an /api folder, and in that folder is the file api.aspx (i.e. you hit www.foo.com/api/api.aspx)
How can I set things up (either via Web.config rewrite or via MapPageRoute() in Global.asax.cs) so that www.foo.com/api
hits /api/api.aspx not /api/Default.aspx
doesn't show api.aspx in the browser's URL box (I just want to see either www.foo.com/api or www.foo.com/api/)
I would have thought that this would work:
routes.MapPageRoute("ApiRoute","api","~/Api/Api.aspx");
but it doesn't... I still hit /api/Default.aspx
EDIT:
I also want to support /abc/abc.aspx and /thing/thing.aspx, mostly so when I have these pages open in the IDE they're not all named "Default.aspx" and I can't quickly see which page is which.

Answer 1

I've created a small demo project. Each folder I want to set a specific default document I add a web.config file.
project structure
Each web.config file defines a default file for it's folder.
web.config in folderA
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<system.webServer>
<defaultDocument enabled="true">
<files>
<clear/>
<add value="a.aspx"/>
</files>
</defaultDocument>
<modules runAllManagedModulesForAllRequests="true"/>
</system.webServer>
</configuration>
Accordingly for folderB
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<system.webServer>
<defaultDocument enabled="true">
<files>
<clear/>
<add value="b.aspx"/>
</files>
</defaultDocument>
<modules runAllManagedModulesForAllRequests="true"/>
</system.webServer>
</configuration>
ATTENTION
When I did some tests in my development webServer it did not work. But
when I published my project to my local IIS instance it did work out
all right.
local IIS deployment