@CTScott, hello! I have an European Yaris 1.3 Sol M-MT (Hatchback). I made few moddings on it and when I have doubts I always find the answer in your posts, thank you.
During Christmas holidays I decided to install the electric trunk release. Here you can see the scheme of the setup:

I used the Scirocco Trunk Poppers for the initial push. Everything works fine, but now I would like to open the trunk with the unlock button on my key (I use the OEM key with 2 buttons, Lock/Unlock). If I crimp the "unlock pulse" wire to pin 85 on the relay everytime I push the unlock button or turn the key in the door-lock the trunk opens, and this is not what I want. Is there a way to add a "virtual third button" to the OEM remote key for the trunk opening (unlock-button pressed for 2 seconds for example).
Hope I explained myself and sorry for my english. Thank you and have a great 2016!
Marco