Take some pics of your Foot Controlled mount and post them... it's hard to tell if you can do it, but I'm pretty sure you can. If you can't post pics, here are some ideas to look at.
Take the Head Casing off of your hand controlled T/M. Take off the mount that holds it to the transom, but leave on the stop which keeps your motor in the desired height.
On your foot controlled mount (depending on model) you can either slide the HC tm in from the bottom, attach your stopper, then put the head casing back on. If the pole is too thin for the mount, you can beef it up with some PVC to fit, but make sure that the tm will still turn in the mount.
If your mount is like mine, it has a knob that you turn and it opens up and then you can just put the pole in it, then tighten the knob back down. Like above, you can beef it up a little with PVC to make it fit tighter.
If I'm totally off line with what you're asking, sorry... but I think I know what you are trying to do. Sometimes reading these questions is like trying to solve a riddle!