PHP / Oracle / CLOB 32K limit problem

[joea]

Here is my code:

$qry = "begin  :x := zmm_functions.update_message_by_id('$message_id','$sec_id', '$variables', '$name', '$xbody', '$changed_by', '$status', '$xbody2'); end;";
$ObStmt = oci_parse($this->dbCon, $qry);
oci_bind_by_name($ObStmt, ":x", $returnData, 3200);
$outcome = oci_execute($ObStmt);

update_message_by_id is Oracle function that simply takes whatever is passed and updates Oracle table where $xbody and $xbody2 are CLOB fields. This code above works great up to 32K in $xbody and/or $xbody2. Any ideas?