> since I use the connection pool (before I made the connection myself in
> the servlet) I have the problem that accents and umlauts are not shown
> correctly anymore, mostly because the connection defaults to UTF-8, but
> my DB is ISO-8859-1.

Connection defaults to NONE, but you're right, you have to specify the
encoding in such case.

> I tried adding "charset"

charSet, not charset, it is case sensitive

> and "encoding" parameters to my context.xml but
> it does not seem to work.

Should work. Did you specify the correct encoding name:

http://jaybirdwiki.firebirdsql.org/jaybird/doku.php?id=config:char_encodings

Also check whether you also set the correct encoding to your output stream.

> Where can the connection charset be specified when using a connection
> pool ?

If you use the DBCP, you can pass it via JDBC URL:

jdbc:firebirdsql:<host>/<port>:/path/to/db.fdb?encoding=UTF8

Roman