If your shooting full manual (and dont need ttl) you can bypass the chipboards as a workaround.
From memory, in the hotshoe, the centre pin is the trigger and the outside of the hotshoe is the ground. There is a small chipboard inside the hotshoe that will make the connections via springs to the hotshoe. You'll just need the trigger wire solded onto the centre pin point on the board correctly, and then have the ground wire solded onto the little metal spring clip that makes contact with the outside of the hotsoe.
Make note of these two wire colours and run these to the trigger/ground of the bulk head using the following diagram.