Thats a reasonable approach.
They ship with a 50k in series and a 50k pulldown, so I think if you put a 5k (4.7k should work too) in parallel with the existing series resistor (easier than removing and replacing it) you will be left with the equivalent of 4545 ohm resistor in series. And the voltage drop across the series resistor should be less than half a volt leaving 4.5 volts which is plenty.
It is the rightmost blueish colored resistor in this pic
