I've been grappling with this since the 747 v3 was released but unfortunately it seems that FSPassengers is simply just not compatible with it.
Your best bet is to also post this over at the FSPassenger forum, it can certainly use the added attention. I'm not counting on much support from the developer but hopefully maybe some in the community will eventually find & share another workaround.
For now it's reason for me to look into alternatives. I've enjoyed many hours with FSPassengers but i'm probably moving to FSCaptain.