That's interesting. I have a similar two-ticket, hand-baggage only transfer at KWI in a couple of weeks, and was resigned to getting a visa (on arrival) to go landside to check in for my second flight (SV). I'm pretty sure full online check-in isn't available: airlines seem to have upped their vigilance checking documents before issuing boarding passes. Maybe there's a transfer desk airside that takes care of that. We live in hope .