Traditionally, I've taken them to a tech to solder in new pickups, I had the shop fit my Black Dog set in my Tokai.
Recently, I bought a beaten up Ibanez Iceman (a 1980 IC50), that had been refinished red by hand (you could see the brush marks!) and had a pair of Ibanez V5 bar type pickups (16.5k Ohm), but they sounded a bit too much 80's for my liking. I took them out, and put the SD's from my Love Rock in it. No sound! After checking everything twice, I admitted defeat and took it to the shop where I got the BKP's. After a bit of investigsating, they had to replace the switch and it's wiring. Anyway, I recently re-refinished it, and fitted the pickups myself, and amazingly, it works (even looks half decent too!).