Originally Posted by VooDooDaddy
Simply cut the female end off the lead in the picture, solder the power wire from your accessory outlet you bought to the black/white wire in your picture, and then solder in the ground wire from the accessory outlet to the brown/ground wire.
Easy, peazy, Japanezzy.
They could also cut that female plug off and attach those wires to a power distribution block's input ports. Then they could attach their accessory-plug wires to one of the sets of output ports. Any other low-amperage switched items they want to power could be wired from this distribution block.
I'd check the amperage rating for that plug's circuit before wiring in a bunch of stuff though.