Cannot transliterate character between character sets

Hi all,
Delphi4,
Interbase 5.1
I try to update a value from a string field and set the value to : " TEST &
C'
I guess that the characters & and are refused.
I get this beautiful message : Cannot transliterate character between
character sets
Before building my database, character set is : Win1252.
What character set should I use to have these special characters in my data
?
Regards