Try using the flash separate to the camera. I have a radio trigger attached to FT1 which triggers 4 flashes guns.
The normal method is to use a dark environment (does not need to be pitch black):
– activate camera (either bulb or longer shutter speed)
– make drops
– trigger flash(es)
– let shutter close
In this way it is the flashes that take the photo.
There is normally too much lag when triggering the camera. You also do not normally get a fast shutter speed. With my Canon, I have found the delay from trigger to shutter is not always the same.