Should be possible via the app too:
Hook up C4 to your phone via USB. (You need to be on the latest firmware for usb communication via mobile to work and updates can only be done by downloading the latest desktop editor and updating from there.)
Press “burn/recall” in bottom bar, select the desired internal preset and press “recall”.
Then press “save” from the bottom bar, rename and add description if desired, then press “save”. It’s now in your library.