Hi José,
Nice to be friends again, after so much discussion. Sorry if some of my words seem hasty. I have tried to research about the Hohenzolern-Sigmaringen and did find out they have a factory up north and were always close to Portugal. They have not forgotten Dona Antonia's legacy. I have been told they are simple and discreet and never mention any rights to anything that is Portuguese. Their factory is called «Zollern» and it is in Maia, near Oporto.
As for Maria Anna's wedding contract, it was published in 1859. Rocha Martins, of course, alludes to it often, specially in texts of «Ilustração Portuguesa» (1900's) and «Arquivo Gráfico» (1930's). Rocha Martins, as you for sure know, is the royal historian who published many of the known facts about the Royal Family for the first time. He was a militant royalist until the death of King Manuel II. After that, having given up the idea of a Portuguese pretender who could follow the Liberal legacy, he turned to the Republic instead. I think I read it somewhere that Salazar was terrified of his chronics and the newpaper boys used to sell the night titles screaming: «Fala o Rocha! Está o Governo à brocha!» («Rocha speaks! The Government is ... well... how do I put it in English... er... in a mess??»)
I'll check if I can get the whole text of the contract and post some of its 18 items when I find it.