I installed mine on the usual position and not one person ever questioned it. They all figured it came with the car. It's saved me twice when I locked my keys in. You say you can unlock your trunk with it? How?
As long as you like where it's stuck, that's what's important.
Mine came with directions which I assume can be googled somewhere but if you hit 5 right after putting in your code, the trunk releases. Same thing with opening the passenger door, think it's 3. Lock both doors by hitting the last two buttons at the same time.