httpHandler适用于虚拟目录，但不适用于类似配置的网站

I am setting up a 3rd party website which makes heavy use of httpHandlers. When configured as a virtual directory under Default Site on a 2003/IIS6 machine, everything works as expected. When configured as a standalone site on the same machine, pointing to the same directory and web.config however, httpHandlers do not work (404).I am setting up a 3rd party website which makes