BUG #13965: Maybe a problem with ODBC UNICODE driver working like ANSI

The following bug has been logged on the website:

Bug reference: 13965
Logged by: Bat Go
Email address: baptiste(dot)gonod(at)gmail(dot)com
PostgreSQL version: 9.3.0
Operating system: Windows 7 PRO x64
Description:

Hi,
I've transfered an ANSI database to UTF8. And when I use the UNICODE ODBC
driver (with simply php file), it's the same result as using the ANSI ODBC
driver (so bad accents cause data are in UTF8). I've tried with an other way
to get my data (pgsql) and there's no problem.
So I concluded the UNICODE driver is bugged !

Using pdo in php to send query :

ERROR HERE (using odbc) :
$connec = new PDO('odbc:odbc_utf8');
and odbc_utf8 configuration :
data source : odbc_utf8
server : my_server
User Name : postgres
Password : pwd

NO ERROR HERE (using pgsql) :
$connec = new PDO("pgsql:host=192.33.50.178;dbname=database", "postgres",
"pwd");

I don't know if there's something in the apache or php conf which can cause
this !