You will need the N90M-ACC Remote cable from Pocket Wizard, it's designed to work with the Pocket Wizard Plus III and the Mini Flex TTI5. It runs about $115.00 USD. You might need another Mini Flex but don't hold me too that as I don't use the Mini Flex.
The reason I say that is that I use one Pocketwizard III on the hot shoe of my D3/s and one in my hand to fire the shutter. In addition, the N90M-ACC will auto focus the lens-which is pretty nice.
I just purchased one about two weeks ago when I upgraded to the PW III from the Plus II.