You can use Pedals conncted to the Pedal 1/2 inputs on the rear panel AND/OR pedals connected to/built in a MIDI pedalboard. The firsts will be seen as Pedal 1 or 2, the seconds will need to be programmed in the MIDI pedalboard to send out MIDI CC messages.
For how to patch parameters to external controllers (hardware & MIDI) and how to setup things in this area you should refer to Eclipse user manual, as it offers a very detailed section on the topic, "Modulating Parameters Via the modulation block: LFO, ADSR, Envelope, MIDI, Pedals, And More", starting from page 40 of latest V3.51 Release manual. It will be very helpful to follow the complete instruction provide there.
The pedal needs to be a simple volume pedal, wired w/a stereo 1/4" jack, with a 0-5 volts value. Most Roland, Boss, Bespeco, Proel pedals will work and can be calibrated on Eclipse to properly cover the expression range.