Did you connect it's video via hdmi ? This will not work ...
you should connect the BM5 via the VGA input and not via the hdmi.
The BS3 detects it is a BV9, so it assumes a BM1 is build in in the system, connected via VGA...
if the ML cable is connected it should work when you select PC
you do not need a IR input on the BM5
regards
nico