Ah, that makes more sense. Even with the right connection, pedals that have a momentary input like that are difficult to work with because you can never be certain what the pedal will do. Sending a momentary pulse to the pedal's input switches the pedal off if it's on, and switches it on if it's off. You can't specifically tell it to turn off or turn on. This can lead to the pedal being out of sync with the controller.
I recommend plugging the pedal into the Hex loop normally (as if it didn't have a remote input) and switch it that way. It'll save you some headaches in the long run. If you want to continue to try the remote switch method, you would probably need to add actions to the button like this:
HEX / CC Toggle (turn the loop on)
System / Wait 100 (wait 100 milliseconds)
HEX / CC Toggle (turn the loop off)
Make sure that Direct Send PC/CC is turned on for the Hex device in the Devices tab if you're going to try this method.