Hey folks - sorry to necro this thread, but I used google to find others in the same predicament and since I ended up solving the puzzle I thought I would share it.
My dad's trunk has the same lock - he pushed the lock under the handle and when I tried releasing it the lock flipped and snapped shut. Of course he had lost the key years ago and didn't mention that was why he had it set up that way.
This particular lock has two tabs that latch into the socket on the trunk. They are spring loaded and the trick to the lock is that there are two things that look sortof like circlips inside. When you turn these in their respective grooves, the tabs retract, but you can't easily turn both rings because of a protruding ridge between them.
Grab yourself a paperclip and rotate the shroud until you can see straight through the shroud and the notch in the first ring. Basically you need a tiny horseshoe shape to ride the two grooves and rotate the two rings that push the tabs to open the lock. I remembered what the key looked like and used needlenose pliers to fold the paperclip into the right shape/size.
It looks like this:
Once you have this, you nest the two notches into the groove and push them into the gaps in the rings, then while under tension turn clockwise. With a few tries you should scrape both rings with the tool and the gap in each ring will 'catch.' You'll know you are on the right track because you may just get the front ring (releasing one tab) and not the other - but sometimes if the lock is loose enough on one side that will be enough to stick in some leverage and pop the other side.
With a little more patience you will grab both rings and release both tabs. You don't need a ton of tension to release the tabs - it is more about getting the tiny paperclip loops to stay in the groove while twisting under tension.
