I use a Mission EP1-KP with my Stage. On asking Mission for direction I got the following response.
“The Mission EP-1 and SP-1 are the recommended expression pedals for use with the NeuralDSP Quad Cortex. Currently only the expression pedal function is enabled. Support for the toe switch will be added later. Customers who wish to purchase the SP-1 now, will be able to use the expression function only until the switch feature is available in the Quad Cortex. Alternatively, the EP-1 can be used if the toe switch will not be required. It’s possible that the EP1-KP expression pedal function will work OK. The switch function has not been tested.”
I hope this helps any other Mission fans.