Hi Roberto, hmm, the dual screen Iconia is not part of the offical Win 8 upgrade program. As such there is no official support. Having said that, I can tell that I have seen a Win 8 preview version running on an Iconia without problems.
I have installed Windows 8 on my dual screen. There are 2 things that dont seem to work right. The Acer Virtual keyboard and the Intel Badge errors out. Not a huge deal, just close out of the badge. And you will need to use the Microsoft virtual Keyboard. This is okay, except that the key placement is different and it's missing the pgUP/DN, Insert & Delete keys that I use often. Maybe if enough people ask they will produce a updated virtual keyboard for Windows 8.
I have an ACER ICONIA 484g64ns, which is the french equivalent of the ACER ICONIA 6120 with 2 touchable screens. I could manage to install Windows 8 professional, and agree to waive to ACER ICONIA gadgets (virtual keyboard and so on).
The main and BLOCKING problem I have with this machine is that it becomes crazy ; after a short time using it, the top screen behaves as if plenty fo touches were done, hiting the screen, turning the machine in an uncontrollable device.
You can easily see (google : ghost touch ACER) that a lot of people face this problem. ACER silence is deafening. I don't want to loose my time being in contact with the customer service, as they play the austruch and deny existence of the problem. The fact is that this problem corresponds to conception and manufacturing defect from ACER.
I do regret having bought this ICONIA for 1500 €
I am thinking of what I will do in few days, maybe go to the court to get my money back (the machine were boucht by july 23, this present year 2012, and is under guaranty until july 2013).
Unless ACER acknowledge officially the problem, get out of its silence, WHICH would not be a bad advertising as they are problably thinking, and provide a fix