Thanks for your answer.
I wanted to test it, and downloaded the latest gpEasy_3.5.2. I found the gpconfig.php, and as you told me:
$upload_extensions_allow = array();
$upload_extensions_deny = array();
But my surprise is that this new release of gpeasy the extension I wish (and many others, even silly one) all of them seems to work.
So the good news is that I have no problem anymore. Gpeasy is progressing so quickly ;-)