1. Walk up to your friend and punch him until he is unconscious.
2. Enter the loot window but don't take anything.
3. Wait (with the loot menu open) for your friend to regain consciousness.
4. While you are still in the loot menu, wait for your friend to exit the server.
5. Once he has logged-off you can take all his gear.
6. Wait for him to log back in, now both of you have identical gear.
Me and my friend tried this a number of times and it always works.