We have a breakthrough!
I figured out the pin-out for the P-005 pedal, and how it works. Kudos to Fraser for bringing me back to this thread.
Going from previous messages in the thread, we know that the pedal port (on newer stations) is a T.R.S. plug, with ground being on Sleeve, and Tip and Ring go to two separate pins on a micro-controller (in the case of the de-soldering module MSE-A, it's a PIC.)
Looking at the manual for the P-305 pedal module, which includes a P-005 pedal and a module to control a single tool that plugs between the stand and the station, I noticed there's a dip switch in the module to reverse the pedal's effect (like depress pedal to heat tool, instead of press pedal to heat tool). the switch looks like a simple SPDT slider switch, which led me to think that IF the module is just a junction box with no brains, then the rest is in the pedal. Can't lose in trying out stuff right, this thread has been going for five years, so what's a few minutes tinkering....
And if the rest is in the pedal, and there exists a dumb adapter to plug the P-005 pedal in older stations that only require a switch as a pedal (going on the manual for the JT6040 that Fraser got), then the P-005 pedal is just an NC and an NO switch that are ganged up, and the adapter just keeps the NO switch and ignores the NC switch!
And I guessed right! It works both on my JTSE station and my MSE-A extractor (if you're trying this, remember that you have to tell the station that there's a pedal connected.)
I guess the station is constantly looking for two state changes at the same time on the TRS plug. One line is looking for a state change LOW>HIGH on pin T, and the other is looking for a HIGH>LOW state change LOW>HIGH on pin R.
Welp, there you have it folks! Enjoy the pin-out for the pedal! to think I picked this up today trying to find some digital signals for the station to talk to a micro-controller in the pedal on startup...