I've uploaded fbintl2.dll (for Firecird 1.5) implementing
this features to the Architect file area:

http://groups.yahoo.com/group/Firebird-Architect/files/charsets_and_collations/

> There is a way to have character escaping in string literals,
> it's only somewhat obscure (but easier to use than
> ascii_char):
>
> As character constants with escaped special characters can
> be seen as a rather funny multi-byte character encoding,
> you just have to define this character encoding in
> fbintl2.dll.
>
> I did a test with a character set LIKEJAVA, which understands
> the \uXXXX UNICODE character escapes of Java, then things look
> like:
>
> insert into t1 (c1) values (_LIKEJAVA'A\u0008B\u0009C\u00C4D');
>
> which inserts the seven characters:
> A
> <backspace>
> B
> <tab>
> C
> <CAPITAL LETTER A WITH DIARESIS>
> D