Works as a pedal switch (ie damper pedal) without issues.
When connecting it as an expression pedal to a continuous input, the outer two contacts of the 6.35mm plug need to be reversed (if you look at the plug as a stereo plug, the L/R channels need to be reversed). The Promega 3 will then send controller values in the range 8..126 through its MIDI out port reliably. Normally it should be 0..127.
When connected to the damper pedal (switch) input connector, the pedal will only work with polarity reversed (the controller will then send CC64 values of 0 and 127). When connecting it to the expression pedal input of the Akai device, no polarity reversal is needed. The Akai controller will then send CC event values in the full range 0..127 over its MIDI output.