Solved Dynamic Permission Nodes

Okay, so I know the default way of implementing permission nodes into Bukkit is through the plugin.yml. But due to the nature of the plugin I'm writing, I don't know what the value for the permission is, as it contains a dynamic variable.
So for instance:

Code:

commandSender.hasPermission("plugin." + unknownString + ".use"); 

The permission is requested from within an Event. So using Command.setPermission() isn't possible.

How would I go about adding this permission so Bukkit knows what is Permissible for what plugin?