Good evening Marino,
Sorry for your trouble.
As the first line of defense on this forum, I must humbly admit, that I know as good as nothing about 5.1 and other Surround setups, mainly since I’ve never had one myself.
All I can do, is redirect you to an already existing thread on the topic (see below) where I will add your concerns; and tag FxSound’s lead audio engineer on your behalf, to notify him of your issue.