For those who are using an emerald ECU (or is it just me!) you'll probably be pleased to know that Emerald are, hopefully, soon releasing new firmware with a much improved CAN Protocol.
This update extends the ECUs CAN protocol and adds additional CAN options. Also, any analogue or switch input channel can now be assigned to a CAN data input instead of a physical input.
I'm using (wasting) several input and outputs on my PDM that I will be able to move to the CAN stream. I've emailed George to ask if the Emerald CAN config file can be updated.