Hi Steen.
Me again...
I've fitted a multi-LED flash system into Denny's KT and Panther.
The problem with the JP is that the gun pivot goes through the barrel, making it difficult to get a decent sized lead to feed the LEDs.
For the 75mm barrel, I used three 5mm LEDs, and for the 88mm I used three 8mm LEDs.
The trigger is taken from the Benedini board, as Mark says, but a PIC chip flashes the three LEDs independently, to give a more random effect. The LEDs are yellow and orange, to give a realistic multicoloured flash effect.
Adrian.