I have the exact same setup, a Control Freak and a Bellman 55ss I bought to accompany my Flair 58+ hand pull espresso machine.
I bought my steamer before the Control Freak and found it very difficult to use on my range. For one thing, the grate over my burners isn't that great for balancing the steamer, and too much heat sneaks around the sides. I've already had to replace the handle once because it got overheated and the thinnest part of the Bakelite handle where it meets the unit cracked and came apart.
It never occurred to me to try the Control Freak until I saw this post, but I spent the afternoon experimenting. I discovered that you don't need an induction plate at all. All you have to do is position the Bellman so that the center nut in the bottom is sitting right on top of the temperature sensor of the Control Freak. If you slide it around, you'll feel when it's on the temperature sensor. To test things out, just put some water in the Bellman and leave the top completely open and put it on your Control Freak set to 100°C. You'll get a message prompting you to make sure the cooking vessel is positioned covering the sensor, and just hit Resume. It just works!
My next task was to figure out how to go about getting the right pressure. The trick is to heat the water in the steamer to the correct temperature for ~2 bars of pressure, and you want to make sure that you don't trip the pressure release on the Bellman. That's there as a failsafe, but you're not supposed to depend on it—just imagine the consequences if that pressure release were to fail for some reason, which is one of the reasons I never liked the idea of using it on my gas range either.
According to my water vapor pressure calculations (example), 120°C is the required 2 bars of pressure. The optimal amount of water in the Bellman is 250 g, so add that to the vessel and screw the top on to be reasonably tight with the steam wand closed. Set the temperature to 100°C at Fast intensity (it will overshoot by ~15°C or so). Once it reaches temp and beeps, set the intensity to Slow and then put the temp to 120°C. You can go as high as 125°C, I was able to get it to 128°C before the pressure release triggered (which is just around 2½ bars, as advertised).
Once it's at 120‒125°C, remove the steamer to a silicon / cork / whatever trivet or hot pad, something stable, and you can go to work. Even off the heat, there will be more than enough pressure to steam a good quantity of milk. I would not try to steam right on the Control Freak because the upward pressure of the temperature sensor makes it easier than I like for something to go wrong.
Keep in mind that even on the lowest intensity setting, the Control Freak heats pretty quickly. Make sure to have a trivet next to the unit and make sure you're standing there so you can quickly remove it if the pressure release triggers. I'm certain the Control Freak is easily powerful enough to produce more steam than the pressure release can vent, and it wouldn't take long to turn into a bomb if left unattended.