There is no such a thing as the "Kingdom Treasury". In Perisno 0.8, they made every walled fief have his own treasury. There should be on-screen instructions on how to add or retake money from it as soon as you enter the Lord's Hall.
When you enter your fief it should pop up in the corner. Numpad 1 to add 10k and numpad 2 to take out 10k