Same problem here. I ordered a battery with a 'thermistor' and will simply match up the wire colours to how they previously were & report back. It should be a pretty straightforward soldering job.
As far as I have understood a thermistor is something like a thermal regulator, likely to prevent overheating. Seeing I can't find anything like a 'ground wire' with this type of battery (I know grounding is something done in relation to batteries/electronics but that exceeds my rather limited knowledge), I think it should be a thermistor.
If someone could explain a little more though that would be great.
I'm assuming with the ground wire they might have meant the one labelled GND?
[image|1816621]
The battery I bought.
[image|1816622]
Good luck!