Modified keybinds where user can use thumb mouse buttons (or any other mouse button, other than LMB, RMB and MMB), even as combo binds, are not detected by the game when player is in Zeus/Game Master interface. They work for any other action that does not involve being in Zeus interface.
To add more, custom keybinds that are introduced through CBA (like Wargame RTS mod does) also don't seem to support #4-#8 buttons if they are meant to be used in Zeus interface.