Here you go:
My idea was to use negative scale for left chart, this will result on Axis to the right / right aligned bars.
So I used a '-' in both expression on the left chart to get negative values.
Problem is that you don't want to show the values as negative.
Here I used number formatting, there is an optional format specifier for negative numbers (see format tab (ah, I just see that this is hard to see since I replaced the expression labels by blank, but there are expression number formats set ;-)), I just set the format to show same as positive (without minus). This affects the values on bars and the tool tip.
Unfortunately the axis will still show negative values, so I removed the axis (maybe I missed a simple solution here).
We should use same absolute scale range for both charts, I set it manually to 0 to 15, but it should be good to enter enter an expression here that checks both charts value ranges and set the same value. Even if you don't see the axis drawn, I think different scale ranges will be misleading.
The rest is mostly formatting (remove all expression labels, use text boxes instead, etc).
I added another version of the chart where you could probably better see what I did, as I said, it's a hack.
Hope I haven't missed anything, if you have problems, give me a note.
Regards,
Stefan
