Dear friends,
ALL the problem solved by a service technician :)
So, we figured out (also thanks to Nobby for his help), that in my MX5500 TV only the 2.1 software was able to handle the same time the two way system, and the motorised stand.
The 2.2 has the ability to control the stand, but the TV lost the two way system, the below versions (fe.: 1.6) was not able to control the motorised stand, but has the ability to use the two way system.
The only thing that the 2.1 and above systems are not able to handle is the "normal" vs. "extended" sound option, it can be set in the version 1.6 only, and no way to change it later.
Thanks for all the help to all, who helped :)