a2ps regular expressions do not match correctly

[Nikos]

I have a file which is in Greek iso-8859-7 encoding.
I am invoking a2ps with -Xiso7 , the postscript file generates correctly and
displays all the Greek characters ok
However I am using regular expressions inside my custom style sheet to match
words with \\w+ and this does match only the latin1 characters and not the
greek characters.

The style sheet I am using is simple-just:

   operators are
       /(\\w+1)/ \1 Label_strong
   end style

However by using the class
  /([[:alpha]])/ \1 Label_strong
it matches all characters,latin AND greek

When I try to do an exact match of a character by using its octal number
(for example capital letter iota is 311 in octal)
(/(\\\311)/ \1 Label_strong)
it does not match anything
When I use the octal code for small letter iota (\351) it does match all
iota's capital and small as well!!!
(/(\\\351)/ \1 Label_strong)

Can someone provide a hint on what is happenning?
a2ps version in Windows is 4.14 and in Linux 4.13b.They act the same on both
platforms

Thanks