the magnet is just above the bottom screw on the trigger, there should be a threaded hole, if its empty there is no magnet in your marker, to be honest it works fine just on microswitch, use the debounce and sustain rate settings to try and stop it bouncing, check the zdspb link and he will have the blackheart manual on there somewhere.
just checked zdspb and he doenst have one!!!!
its an odd way to get it but there is no link through the main page
blackheart manual