probleme avec utl_smtp_data

j'essaye d'uliser les outils d'oracle pour envoyer un courriel
voici la procedure

(
sender IN VARCHAR2,
recipient IN VARCHAR2,
message IN VARCHAR2)
IS
mailhost VARCHAR2(30) := 'mail.vigie.com';
mail_conn utl_smtp.connection;
BEGIN
mail_conn := utl_smtp.open_connection(mailhost, 25);
utl_smtp.helo(mail_conn, mailhost);
utl_smtp.mail(mail_conn, sender);
utl_smtp.rcpt(mail_conn, recipient);
utl_smtp.data(mail_conn, message);
utl_smtp.quit(mail_conn);
END;


si j'execute cette procedure

exec savoie_send_mail('michel.savoie@vigie.com','michel.savoie@vigie.com','test héhàhî');

je recoit le courriel
mais je perd tout mes accents

hel,p please