Inheriting Family Name in Different Faction

[Black Knight]

I've noticed that when I marry a princess to a foreign general, their children get a random surname. This happens of course because that general's surname isn't part of my country's name list, but could there possibily be a way to solve this?

Btw, I'm playing SS 6.3.

[Ishan]

There is no way the new names are chosen randomly from the names list of that faction and the only non-convincing workaround is by giving the two factions same names.

Like English were Normans so a few common names with the French would not hurt.

[Black Knight]

It would make sense, but even that's not working. It seems that even if the general's surname is part of the faction's list, his children will get a random name.

And I'm pretty sure the name works, I've tested it on other characters of the intended faction.