To add to Peter's response, generally, as long as you can connect the device via USB without having to use some special driver package (e.g. like UA audio interfaces, many BOSS mid-rang MFX units, etc.) then it should be compatible.
Having a quick look at the Roland docs for this device, there is ZERO mention of any MIDI specs.
The only reference to MIDI is when it describes that micro-USB port:
USB cable (micro-B type)
You can use a micro-USB cable to connect this unit to your computer, and send and receive MIDI data.
So, this is not a good sign...
A quick internet search turned up this YouTube video (https://www.youtube.com/watch?v=7WYDpHrQmXc) based on the SPD-1W (I think this is in the same family of devices?) where the author found that it is hard-coded to transmit a Note On command on C3.
So, you might want to follow the above video.
Once you have the SPD pad connected to your iPad/Macbook, in Stage Traxx, you'd go into Remote Actions and select the action you want to assign. It will go into Listen mode, at which point if you hit the pad Stage Traxx will (hopefully) register a Note On command for that action.
Good Luck!