>I think Emacs developers are much more motivated to improve the
>multibyte mode than to fix the unibyte mode.  I cannot speak for the
>head maintainers, but that is certainly my opinion: the unibyte mode
>should simply die, as a mode for interactive editing.
ok, I will not use unibyte mode :)

>You received several suggestions for trying things in multibyte mode.
>Perhaps you could try them and see if they allow you to edit your
>programs without screwing up the cp852 characters.  If something is
>still wrong, please describe the problems here: we are much more
>likely to find a solution for multibyte mode editing than for unibyte.
so, my only problem (in multibyte mode) is annoying question for safe coding 
when saving buffer, I attach a new screenshot:
- on the most upper buffer you see my file which has originally some cp1250 
chars and also cp852 chars, 
- on the middle buffer you see that I have cp1250 set to save this buffer, 
- and below there is a buffer with information that there is no possibility to 
encode \210 char (originally cp852) to cp1250 (because cp1250 is my codepage 
to save, but of course after saving this char in the file should be cp852 
coded and it will be when I force cp1250 - this is ok)

I can't find any way to force emacs not to prompt me with codepage selection, 
I understand emacs treats it like an error (in his opinion \210 char is 
wrong) but I would like to set somehow that cp1250 is safe,
"-*- coding: cp1250 -*-" or modify-coding-system-alist function is not 
solution

my only question is: how to configure emacs to omit this codepage selection in 
such situation? 

I would be thankful for help!