Charset and encoding

Hello,

    I have defined a database with the encoding SQL_ASCII. I fill the
database by using embedded SQL. When I insert the value "Señales", it is
correctly inserted. I read the correct value by typing the query in
postgres, but when I access this database from a Java program, via JDBC,
I obtain the value "Seqales". The LANG variable is set to "es_ES"
(spanish) which I suppose is OK.

    I have changed this database encoding to LATIN1 and set the client
characterset to LATIN1 by typing  \encoding LATIN1.

    Now when I access the data from postgres interface I obtain
"Se(82f1)ales", and when I get the value through the Java program, I
obtain
"Se ñales".

    Does anybody knows what is happening? Where can I find information
about this?
    Thanks in advance,
    Rosa M. Carro