Character encoding issue with PDO_ODBC

Question

When accessing a Microsoft SQL Database from PHP using PDO_ODBC with the following code, I have an encoding issue. When outputed the text from the DB is garbled.

$dsn = "odbc:DRIVER={SQL Server};SERVER=$hostname;DATABASE=$database;charset=UTF-8";
$pdo = new PDO($dsn,$username,$password);
$sql = "SELECT text FROM atable";
$result = $PDO->query($sql);
while($data = $result->fetchObject()){
  $values[] = $data->text; 
}
dpm($values);

This is done from a Drupal module. Everything in Drupal is made to work with UTF-8. The cleanest solution would be to able to retrieve the data from the database in UTF-8 or to convert it UTF-8 before outputting.

I tried these without any success

• $dsn = "odbc:DRIVER={SQL Server};SERVER=$hostname;DATABASE=$database;client_charset=utf-8"
• $dsn = "odbc:DRIVER={SQL Server};SERVER=$hostname;DATABASE=$database;charset=utf-8"
• $pdo->exec('SET NAMESs utf8') after new PDO(...)
• $pdo->exec('SET CHARACTER SET utf8'); after new PDO(...)

PS: The code is currently developped on Windows but it has to work on GNU/Linux too.