Re: Seymour Duncan tech support
Firstly, you can calm down. This will be easy to figure out. The Duncan guy is human; he isn't perfect. Duncan is generally a fine company, but they're run by human beings, who are very far from being perfect and all knowledgable.
The original bridge pickup sounds like it's splittable to only one coil, so it was made with only one extra wire (like old Dimarzio Dual Sounds and other early splitting pickups used to be). Ibanez wires the switch so that it only needs to be able to split to one coil, so no need for them to include the fourth wire, I guess.
The Ibanez switching scheme is what is generically called "auto split" switching for humbuckers in a Strat (or any guitar with HSH and a five-way blade switch). It automatically splits either humbucker into a single coil when you go to the #2 and #4 "notch" positions. This gives you some semblance of "traditional" Strat notch positions, instead of having the humbucker overwhelm the tone.
So, you are going to wire up your Dimebucker for "auto split." This is really no different than the Ibanez pickup, as you still end up with three connections from the Duncan. You just need to know which Duncan wires to group together. You are going to keep the black separate, and it will replace the hot lead from the Ibanez pickup. The red/white on the Duncan will be grouped together, and will replace the splitting lead on the Ibanez pickup. The green/bare on the Duncan go together, and will be your ground connection.
Once you do this, it is possible that the polarity will be the opposite of the stock pickups. In that case, you simply swap the green and the black wires on the Duncan. Or, instead of trial and error, you can look this up ahead of time.
If all else fails, try to dig up a generic wiring diagram for auto split mod with 5-way import boxed switch and V/T knobs using a Duncan pickup. Or you dig up the same chart but with an open blade switch, and then track down a boxed to open blade switch conversion key.
If you had been able to tell the Duncan guy that the guitar has auto split and uses a boxed blade switch, maybe he could have done a better job figuring it out. Who knows? The important things are that it's not hard to figure out, and it isn't worth dumping Duncans because one guy who works there was ignorant of your needs.
. Because, that's how we roll. 
