i use turkish charset (iso-8859-9) on linux (centos 4.1) side and no trouble with turkish charset on mounted share via smbfs
i use following:
mount //w2k/g$ /mnt/2k/g/ -o username=administrator,password=*******,iocharset=iso8859-9,codepage=cp857,ro
iocharset should be set to charset which is used on linux side. and u must have correct console fonts to see your language charset. i use "lat5-sun16" for "iso-8859-9"