[plt-scheme] Using web-server/servlet-env to host a root level servlet

Hi,

I'm trying out the web server code described here
(http://docs.plt-scheme.org/web-server/servlet-env_ss.html), but I
can't figure out how to make my servlet hosted at the root level.  For
example,  the program

(require web-server/servlet-env)

(serve/servlet
 (lambda (req) "hiya")
 #:servlet-path	(string->path "foo.ss"))

gives my a page at http://localhost:8000/foo.ss, but changing the path
to "" or "." doesn't work.  Any suggestions?

Thanks,
Rob