Tidy outputs no HTML-Entities

Hi,
My problem:
Tidy outputs ISO-8859-1 characters (German Umlaute) instead of HTML-Entities
- it changes HTML-Entities to ISO-8859-1 characters.

Example input:
Ü, ü
Example output:
Ü, ü

But I need:
Ü, ü

Tidy is running on a server within a CMS (as the last instance, the output
is coming directly from Tidy); I have no idea what version it is. I can
access Tidy only via changing the config-file.

If I run the same config-file on my local server, everything works fine - I
get HTML-Entities in the output.
Both machines running Windows with Cygwin.

I have no idea what the problem might be, 'cause in the config-file I use
ascii as the output-charset, so Tidy has to output Entities for
Latin1-characters??

Here's my config, thanks in advance for any comment...

input-encoding:ascii
char-encoding:ascii
output-encoding:ascii
ascii-chars:no
word-2000:yes
drop-proprietary-attributes:yes
logical-emphasis:yes
show-body-only:yes
tidy-mark:no
output-xhtml:yes
doctype:strict
wrap:0
force-output:yes
break-before-br:no
quote-nbsp:yes
quote-marks:yes
quote-ampersand:yes


Regards
Eric