As long as you've got 9V motors you can hook up to the Power Functions unit you should be okay, just don't expect it to behave the same way as Power Functions motors do. On the S@H page ROSCO provided there is this: "Allows you to connect your LEGO (...) (16 years ago, 28-Jul-08, to lugnet.technic)
(...) Geoffrey, It also works the opposite way too! I use that wire to connect the 9v Train regulator to my PF motors. Works like a charm! It also gives you speed control.... -Alvin. (16 years ago, 29-Jul-08, to lugnet.technic)
