Probleme bei UTF-8 und str_replace()

[Antman]

Auf reiner sql Basis klappt es auch nicht:

$res =& $this->_db->query("
SELECT id,
REPLACE(REPLACE(REPLACE(REPLACE((CONCAT(c.name_f, ' ', c.name_l)), 'ö', 'oe'), 'ü', 'ue'), 'ä', 'ae'), 'ß', 'ss') AS name,
CONCAT(c.name_f, '_', c.name_l) AS folder
FROM contacts c, lnk_company_contact lcc
WHERE (c.id = lcc.id_contact)
AND   (c.public = '".$public."')
AND   (lcc.id_company = '".$company_id."')
ORDER BY c.name_f");

Aus dem gleichen Grund ?

Wer weiß die Lösung zu beiden Problemen ?