Fuel gauge ciruit

The stock fuel gauge on my bike would go from 100 ohms when full to 0 ohms when empty. I recently replaced the meters with an acewell meter. Unfortunately, the acewell meter shows the opposite of what I need. It displays full when 0 ohms are put across the terimal and ground and empty when it's 100 ohms.

So I need a way to convert the resistance. Basically if X is the termistor's resistance, I need to run (100 - X) resisance between meter terminal and ground. I can't think of a way to do it...

When it's hooked to the Acewell, can you take a voltage reading on the sense wire (relative to ground), when full and empty. Without that info, any circuit would be guess work.