Thanks for the comment on 3,3V. Do you think I should connect it to the 3,3V pin on my Mega instead of the 5V?
If the computer needs drivers for a bluetooth, how you "install"a similar thing to Arduino?
The only manual I've got is this http://www.bizoner.com/download/USB-SSC32_Command_Formatting.pdf. But I don't think it says anything about bluetooth.
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?