change thermistor (104GT-2 --> PT1000) in RatOs.

Hi
I need to change my thermistor and can't find the one that is originally equiped on my Phaetus Rapido (104GT-2).
I saw that I could use a PT1000 instead but it's not really plug and play. I need to change something in the Os and can't figure out what it is.
Can you please help me ?