You must first unlock both drivers side doors, and climb through to the rear compartment.
The forester has a little cap that comes off to unlock the latch as does the impreza wagons.
The 05 outbacks have a small panel that comes off to unlock the latch.
In either case, you still have to go around the outside to release the latch and lift the gate.
From a salesperson, Marc @ Natick Subaru Natick, MA USA