mirrored barplot on with two different scales

i would like to plot a stacked mirrored barplot. For this i need to apply to different scales. I show you the table:

a   b   c
DS1 1   0.082
DS1 2   0.045
DS2 1   0.038
DS2 2   0.013
DS3 1   0.022
DS3 2   0.017
DS4 1   0.028
DS4 2   0.004
DS5 1   0.003
DS5 2   0
DS1 1   -66
DS1 2   -132
DS2 1   -244
DS2 2   -255
DS3 1   -244
DS3 2   -185
DS4 1   -444
DS4 2   -344
DS5 1   -111
DS5 2   -111

this is my code :

ggplot(d, aes(x=a, y=c, fill=as.factor(b))) + 
geom_bar(stat="identity", position="dodge")