Hello again,
after some time I made some improvements for vehicle patch (I would like to see Flame levithian encounter working), I fixed Change seat packet handler. I just guessed packet structure...and I've got lucky Should be working ok now, even with accessories in seats. If you find some bug, tell me.
http://github.com/Tasssadar/Valhalla-Project/commit/08cc00883e05e68d9ab1912c5b7a9afbad806a5a
PS: I hope i commited it right, i just tested if its compileable, not ingame
EDIT: Oh, and also - thanks trinity core for Unit::ChangeSeat idea and one vehicle seat flag, but they have also wrong packet structure - I think it was from 3.0.x, and maybe even wrong - I have never seen such big(well..its not small) packet which wasnt begining with GUID of something.