The green and white wires are always the "coil split" wires on BKP pickups, Tony, so they should be wired where the red and white wires from the Ibanez pickup were connected.
I'm not 100% sure on the next bit, but I think the BKP's black wire should connect to the switch (where the Ibanez black wire was) and red plus bare should connect to ground on the back of the pot. That way, I think, you have the slug coil active in position 2 when both coils are split. So I'm disagreeing with the sevenstring forum diagram, but maybe I'm being thick... maybe you should try their suggestion first. :(
You can test by tapping on the polepieces as you move the switch, to see which coils are active. If it turns out the screw coil is active in position 2, then swap round the red and black wires.
In that second position (or position 4 as it's labelled on your second diagram) both pickups are split, there aren't any "tap" options (although people often say coil tap when they mean coil split :x ).