If you could find the HID report for a keyboard that has those extra keys then we could use that (or at least see how it differs from the one we currently send)...
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It might be related to the 'HID report'? The array at the top of http://www.espruino.com/modules/ble_hid_keyboard.js
If you could find the HID report for a keyboard that has those extra keys then we could use that (or at least see how it differs from the one we currently send)...