You can try other country's eBay sites. Sometimes a Weck will find itself on the other side of the pond, but these were made in the US, and no longer made, so the US ebay is about the only place you are going to find 95% of them.Unfortunately the costs of shipping US-Portugal are prohibitively high.
We pay as much for shipping as for the Sextoblade.
Even if you have to pay double, it's worth it in my opinion. In my opinion, the Weck is the second best shavette out there. The best being the Feather. And with Feather's cheapest model costing ten times what the Weck costs... the Weck is the best value in shavettes for the quality you will find.