[plt-scheme] symbols redefined in SRFIs

Thanks, found the notes. I'm now trying to create my own "language"
which exports the SRFI-1 reverse! as reverse! (and omits the R5RS
reverse). I created a subdir plt/collects/danm and added an
mzscheme2.ss (which for now is a copy of
plt/collects/lang/plt-mzscheme.ss + SRFI-0) and the following info.ss:

(module info (lib "infotab.ss" "setup")
  (require (lib "string-constant.ss" "string-constants"))
  (define name "danm")

(define drscheme-language-modules
  '(("mzscheme2.ss" "danm")))

(define drscheme-language-positions
  '(("Danm" "Mzscheme2")))

)

Then I ran plt-setup. Now the new language shows up in the Languages
dialog, I can select it, and cond-expand works. But I can't create
modules in the new language:

> (module mod mzscheme2 (provide f)
  (define f (cond-expand (plt 1) (else 2))))

require: unknown module: mzscheme2

What's wrong?

-- Dan