Login backend in TYPO3 with Proxy

I use TYPO3 6.2 on Ubuntu behind a Proxy.

When I want to login in the backend, all the times I have this error :

Your login attempt did not succeed

Make sure to spell your username and password correctly, including upper/lowercase characters.

But I'm sur, the username and the password are good cause I try to create an other usr in the install fill and I have the same error with the new user.

I tried to change this conf but that doesn't work too.

[HTTP][adapter] = curl [HTTP][proxy_host] = http://proxy[HTTP][proxy_port] = port[SYS][curlUse] = 1[SYS][curlProxyServer] = http://proxy:port

Edit : I don't use SSL

Edit2 : I need perhaps add something in my conf with Apache (It's compulsory to use proxy)

NameVirtualHost 127.0.0.1:80<VirtualHost exemple.com:80>        DocumentRoot /var/www/        ServerName exemple.com        ServerAlias www.exemple.com<Directory /var/www>                Order Allow,Deny                Deny from all</Directory>        ProxyPass /exemple/ http://exemple1.local/        ProxyPassReverse /exemple/ http://exemple1.local/</VirtualHost><VirtualHost 127.0.0.1:80>        DocumentRoot /exemple/        ServerName exemple1.local/<Directory /exemple/>                Order Allow,Deny                Allow from all</Directory></VirtualHost>