You can access the underlying Java table by running self.getTable() in an extension function (perhaps in the initialize function, but you must know that the initialize is only ran when opening the page).
After that, it should be possible to alter the key bindings like it’s done on a regular Java table, but I can’t help on with that.
This here does about the same, but for click handlers on the header: Catching click and right-click events on power table headers