Hi,
i don't know about coding of UTF, but wikipedia reads that all ASCII characters are UTF-8 characters, so i guess that all characters except non-ASCII character should be visible. am i wrong?
Yes, they will be visible, but I'm talking about SMSs without ASCII chars except spaces/numbers/dots/commas/etc. In that case all words (in national language for example) will not be visible at VTY and user will see many '?' symbols if change non-ascii chars to '?' and spaces/comms/etc, and I think such representation of original text will be not very good (if I correctly understand your first comment).
Thanks, Pavel