Regarding the BT I will contact the manufacturer then. But whatever they say I will still need a BT transceiver from the Arduino Mega, isn't it? Any recommendation on which one?
As I mentioned, just as I don't see anything remotely "Arduino" on the bd shown, I don't
see anything "BT", so before I'd buy a BT transceiver, I'd find out what is really on the
board.
From what I can tell from the pictures, I assume you could connect the bd to any RF
comms link, such as an XBee.
You need to know what you actually have before you can know what to do next.