Did you try to import it in the Universal Device Poller utility and then edit it like you usually do for any other UnDP you create?
Start > All Programs > Solarwinds Orion > Universal Device Poller
File > Import Universal Device Pollers.
Add the UPS Temp. Poller, Save it.
Re-Export the UnDP (if you need).
This is how I would proceed if I had to edit exported UnDPs in which an OID to be polled is missing.
Yeah, this is how I finally accomplished it. I would have thought it would be easier - maybe in the next version.