Look at your superknob configuration. It can be configured to either a CC or Sysex. Best would be to configure to a CC - the standard CC for Superknob is 95 I believe. You can inspect this setting:

1) Press [UTILITY] button
2) Navigate to "Settings" -> "MIDI I/O" menu
3) Lower-right look at "Super Knob CC" setting. If set to "Off" this means Sysex and I would change this to 95 (CC number 95 decimal).

Once the superknob responds to CC messages, setup your FCB1010 expression pedal (whichever one, refer to documentation of the pedal) to transmit CC 95.

I did this years ago with A Roland FC-300. A similar type of foot controller. The downside of using it to control the super knob in this way was that it cannot be used to grab the current position. For example if you switch to a performance where you super knob is all the way to the left but your foot pedal is fully depressed. As soon as you move the foot pedal a little bit, the super knob jumps to that position. And this can sound terrible in a live situation, depending on what the super knob is doing. With the Yamaha FC-7 on the other hand, you have to move the pedal back to the beginning to "grab" the current position before it takes effect - the same way the sliders do with the volume.

I was advised on the forum to get into the habit of moving the foot pedal every time between performance changes. I tried that. I have enough to focus on so I gave up and bought an Yamaha FC-7