Bukkit

Hi,

for the first, thanks for this nice plugin.
I have one question, when i add a permission to buy and a player buy this permission, where are the permissions for each player saved and how can i delete a permission from a player ?
Sorry for this noob question.... :/
I use Pex for permissions, but in the permissions.yml are only groups listed. The permissions must be saved for each player somewhere ?!?

Greetings from Germany