Eduardo,
These holders are available on ebay in the USA and abroad. Which type(s) do you need? There there are turning, facing, milling, tapping and right angle holders for that machine. The one you have pictured looks like a milling holder.
This person has 6 milling holders available from Germany:
Find many great new & used options and get the best deals for MAZAK 51718006103 VDI 50 Angetriebenes Werkzeug Bohr und Fräskopf at the best online prices at eBay! Free shipping for many products!
www.ebay.com