I can't comment on the 580, but I am able to trigger my Jessops flash with the onboad... set the flash into slave mode, and make sure the front of the base is pointed at the camera. The light from the onboard triggers the Jessops flash with an optical trigger. Means you have to have line of sight, and you have to have the onboard active, but it works. I would expect the 580 would be able to operate in the same way.