first, you'll need one of these (or something like it.)
Guitar Parts: Switchcraft 3-way toggle switch for 3 Pickups
for all intents and purposes, for what you want to do, the 81TW is two pickups, not one.
Judging by this diagram
The orange is always connected to the circuit, and it appears that the White + Yellow are for the single-coil part, and the blue and green are for the humbucker part. I haven't yet found a reference for what exactly each wire does on the TWs, so Trial and error might be your best bet. My asumption is that the wires on the "top" in that diagram (yellow/orange/blue) are the grounds (with the yellow and blue running into the orange, which would connect to the shield back at the pickup maybe?), and the two on the bottom (Green/White) are the Hots. I wonder what would happen if you soldered the Y/O/B together, and then the Green to the middle lug, and the White to the neck lug? That sounds like it would work in my head, but I'm really basing everything here off an unconfirmed assumption, so I can guarantee nothing.
EDIT: Fairly sure I'm right about this. the Push/Pull is a DPDT, so, say, with the pot in the down position, the Green is connected to the "Output" and the Blue is connected to the Orange. Orange is the 'negative' side of the pickup (AKA a ground), if it were a traditional pickup of some type. I would solder the Orange, Blue, and Yellow together, solder the shield to ground, and the White (Single-coil) to whatever location you want the single-coil to be, and the Green to wherever you want the humbucker to be.