Yep, the ARB bumper must come off on a 2nd gen to mount the winch.
That is the beauty of keeping your winch from getting ripped off.

http://www.pnw4runners.net/runs/7602/221024.jpg
http://www.pnw4runners.net/runs/4602/181024.jpg

Leo, you might want to add a little security to it too once you get the solenoid pack mounted to your bumper.
A malicious punk could take a paper clip and short out two terminals under the cap and start your winch up.
Not good, especially if they un-spool your line and wrap it over your roof back to your rear bumper.
It would cave your rig in like a sardine can.

Here is my solution.
Further down the page is a Warn Power Interrupt kit.
Your winch power lead goes to a solenoid that goes to a switch you mount in your cab.
The switch must be flipped in order to supply power then to the winches power line.
The Power Interrupts power lead which is the same size as the winches goes directly to your battery.

This will give you peace of mind from the tree huggers.