Cannot bind Alt + Page Up or Page Down

Alt + Page Up/Alt + Page Down are two of my historically used binds for cooldowns in other games. However, it would seem these to button combinations are unable to be bound to perform any action in FF14. The combo doesn't seem to have any default or hardwired action in the game, and the two buttons work with shift and control. It would be nice to be able to bind Page Down and Page Up with an alt modifier.

I remember I had issue with CTRL-ALT-0 and CTRL-ALT-9, check whether there are any other keymapping outside the game (FFXIV), once disabled in "outside" application those mappings are usable. This could be used by Windows itself or any running applications in the system tray.