Sorry for bothering you.
Kodo I sent 3 emails to support, all I got was just ticket number. That was the reason why I post the question on the forum.
I was in the time pressure, because if it would be a clone, I would send it back.
I read all relevant manuals on this page and found how to check originality. It didn't work, no plugin available. I hope, that you will understand, that I raised this issue with the manufacturer.
I bought DM from eBay as used and the seller was claiming, it is genuine. This means nothing to me. I bought it for 240 GBP+12 GBP postage. This means nothing to me. Many people bought clones for the price of original. Average price doesn't mean, that the product is genuine.
I was trying to find as appropriate section as possible. If I put it somwhere else, I'm sorry. I did my best. I didn't put it into DM600, but DM7025 section (I believe).
Today I got an email from Dream Multimedia. The guy asked me for serial number, that he will check originality by SN. I asked him, how is it with the plugin, which they mention on the page as a fighting tool against clones. He didn't say anything about it. He said, that the Dream Box is original (based on serial number). Strange... China has no problem to replicate a hologram, so I cannot see a problem, to buy one original, check serial number and use this SN on 10.000 clones.
However, I got confirmation, that the box is original. When I'll be selling it, I'll use it as a proof.
Many thanks for the help.
Nyrethym