Autodetect dos and unix files in Xemacs 20.4 (mule)

Hi!
 
I'm running Xemacs 20.4 with mule support on Solaris 2.5.
I can't manage Xemacs to automatically detect dos files,
i.e it won't hide ^M.
 
I've set buffer-file-coding-system-for-read to undecided,
and buffer-file-coding-system is set to iso-2022-8.
Coding system will be set to iso-2022-8-unix disregarding
if the file I open is a unix- or a dos-file, 
 
Do anyone know if there's a bug in 20.4 which makes
Xemacs unable to autodetect the file coding to use?
 
M-x describe-coding-system RET iso-2022-8 RET
ISO8 -- iso-2022-8
  ISO-2022 eight-bit coding system.  No single-shift or locking-shift.
Type: iso2022 (variant of ISO-2022)
Initial designations:
  G0: ascii
  G1: latin-iso8859-1
  G2: never used
  G3: never used
Other Form: 
  short-form, 8-bit, use-single-shift
EOL type:
  Automatic selection from
    iso-2022-8-unix, iso-2022-8-dos or iso-2022-8-mac.
 
Then I also would prefer to use iso-8859-1-unix and
iso-8859-1-dos, but that doesn't seem to exist.
 
Thanks for any help.
Jeppe