In my web application I have a route which looks like this:
routeCollection.MapRoute(
\"AdfsMetadata\",
IIS by default is serving that file as static withouth going into ASP pipeline, can you change the route to not have a .xml extension (which is not necessary at least you have a specific requirement about that)
You can specifiy the route like this:
routeCollection.MapRoute(
"AdfsMetadata", // name
"FederationMetadata/2007-06/FederationMetadata", // url
new { controller = "AdfsController", action = "MetaData" }); // defaults
Other solution would be to add to your web.config
but I recommend you to avoid this as possible since what it does is to stop IIS from serving all static files
EDIT Last try... a custom http handler for that specific path would work. This post is similar to your problem only that with images (look for "Better: Custom HttpHandlers" section)