how can i save the symbol 
or any other special character in tags? instead of anything like there's a default windows square. 
do you use utf-16 encoding?
and then: the target system has to feature the same font. e.g. if you found this character in a special font like symbol or so, the target system would have to have that installed as well.
so it could be a problem that special characters have a special meaning on other systems and are thereform masked to avoid trouble.
ID3v2.4 UTF-8
thanks for such massive reply )