The proces it quite simple since they use "fusion blocks" where one side is aluminium and the other is metal. These blocks are produced in Russia in an explosion like way.
So having these blocks you just weld the aluminium to the aluminium and the metal to the metal.
Anyway, i looked for this builder and they turn out to build casco's for Amels, Feadship and a few others!
Maybe this is old news for most of you but i was quite amazed to find out that the base of these marvellous ships is layd on a stonesthrow from my house (and not knowing about it...).
Here is the link to their site: http://www.scheepswerfslob.nl/yacht.html
Anyone with more of these links?