Assuming you're comfortable popping off your bridge and using a soldering iron, you shouldn't have a problem swapping out the pickups.
After you pop the bridge off, after that, it's just a matter of making a little diagram of where each color wire goes from your old p'up to the switch/knob/etc.
Since you're replacing a Dimarzio wih a Dimarzio, the color ocde is the same... just unsolder the old one and match the colors from the new one. It'll take you a good hour or so the first time....I've done a lot of them and i'm down to about 20 minutes
note of caution: Don't overheat the solder points on switch...they WILL melt. The switches Ibanez uses aren't very well resistant to high-heat - keep the iron on them as little as possible.
~K