[plt-scheme] current-locale parameter ignored ?

Hello,

The manual¹ says that:

   String and character printing with write is affected by the
   parameter, because unprintable characters are printed with escapes
   (see section 14.4).

which is perfectly reasonable, but no matter what current-locale is
set to, all characters whose char->integer value is greater than 127
are treated as unprintable (i.e. write is *not* affected as stated
above.)

Has anyone else seen this? 

I was expecting something like:

> (current-locale #f)
> (write "México")
"M\351xico"

(which is correct) and also:

> (current-locale "es_ES.ISO8859-1") ;; or es_MX, de_DE, etc.
> (write "México")
"México"

but this doesn't happen, this latter example also prints "M\351xico".

BTW, this is PLT Scheme v.200 on FreeBSD current.

--Francisco

Footnotes: 
¹ http://download.plt-scheme.org/doc/200/html/mzscheme/mzscheme-Z-H-7.html#%_sec_7.4.1.11