My CSC is COA so I managed to force my phone get the updates from Spain. Since my ROM was really messed up and I wanted a clean install, what I did was first flash Philz Recovery to format everything, then I installed XXKL1 (Gingerbread Open Europe 2.3.6 ROM), after that went to ICS (XXLPJ Open Europe 4.0.3 ROM). What followed next was XWLS8 (old Spanish FOP ROM) which did not allow me to select CSC as it seems the ROM does not come with the CSC selector from ICS. When I plugged my phone on to Kies it showed me some Korean CSC and displayed me the message that this phone cannot be updated via Kies. So I did the following trick: when first setting the phone I did NOT add my Samsung account (I am not sure if it has any relevance, someone can verify if this is actually true, but since my account is already set to a country different than Spain I thought this may screw the whole thing up), but when I set up Software (OTA) Update I selected Spain (Espana) and it started downloading the OTA package and then it updated. What's even better is that after I got the update package I got upgraded to LSD and I was also switched to FOP CSC automatically and my phone which shipped with COA from the factory now runs a Spanish ROM recognised by Kies, able to receive OTA updates.
I have not found much on the internet, but I believe it does matter what ROM you are coming from, I found out that coming from the aforementioned ROMs with Open Europe CSC help you make cleaner installs, at least this is what I can tell you from my experience of coming back to Stock ROMs from various other customs.
This whole sequence of flashing has always worked for me when I wanted to restore to my original CSC 4.0.3 ROM but I have not tested it into changing to a different CSC. It seems that Jelly Bean somehow allows you to force a new CSC and make Kies recognise it and update it (or via OTA). Hope this helps!
