#330 No se trata de negar que fue un casamiento en casa, sino de demostrar que si lo fue. La línea de sucesión se transmitía de manera patrilineal siempre y cuando no se especificara en el contrato matrimonial que se transmitiría de manera matrilineal.
http://libro.uca.edu/payne1/payne5.htm
It was to save Aragón from domination by the powerful Leonese-Castilian monarchy that Ramiro turned to the highly capable young count of Barcelona, Ramón Berenguer IV (1131-1162), a strong military leader and the best Hispanic politician of his generation. Ramiro's infant daughter, Petronila, who was to have been betrothed to Alfonso VII, was instead pledged in 1137 to Ramón Berenguer, with the provision that their offspring would reign jointly over the two states of Aragón and Catalonia. In the meantime, the Catalan count was to exercise the powers of the Aragonese crown, and even in the event that the tiny Petronila died before the marriage could be consummated, the house of Barcelona was still to inherit the Aragonese crown.
Dice claramente que aunque Petronila muriera sería la casa de Barcelona la que heredaría la corona aragonesa, en ningún lugar dice que fuera el conde quién se uniera a la familia de Ramiro.