John and Jeff, here's what I think (of course you can confirm it by calling PAD ;-):
1. The thin ground wire(s) are actually connected (at the OTHER END from where they emerge) to the ground ring of the RCA connector, along with the (connected) end of the floating shield. In other words, the RCA ground ring, the thin wire and the shield are all connected together at one and; and the only thing connected to the RCA ground ring at the other end (where the thin wires actually emerge) is the minus signal conductor.
2. So you want to connect the end of the cables with the thin wires coming out to the tonearm box ane the (both) thin wires to the tonearm box ground lug. PRESUMABLY ;-) the ground lug on the tonearm box connects to (a) the tonearm wand and (b) the turntable-and-motor chassis. In other words, connecting the thin wires to the tonearm box ground lug is in lieu of the fifth DIN plug John mentioned. And if you got your AudioMeca TT/TA as a set, then I'd bet money both (a) and (b) are connected to the tonearm box ground lug and you shouldn't have anything else to do.
3. HOWEVER, if you connect things as I indicated in 2, and you still get hum, it means that only the tonearm wand (2a) is connected to the tonearm box ground lug, but not the turntable/motor chassis (2b). If this is the case, you can either (a) run a separate wire from the TT motor/chassis to the back of the tonearm box ground lug or (b) you can run that wire instead to the ground lug of the phono preamp. Either way will avoid ground loops, but hopefully you'll be fine as indicated in 2.
