Graphs - How to display negative as positive

Hi,

I have table, in which among other columns there is a column with text, other with negative values, and other with positive values.

I'm trying to build a graph with combined columns and lines, in which the line will be based on the positive values, and the bars on the negative values .... BUT I want the negative values to be shown as positives (only in the graph), so the lines and bars will appear on the same graph region.

I wouldn't like to insert a new column in my table only to convert the values, so does anybody know if it is possible to insert a formula directly in the Graph Source Data configuration? I was thinking about ABS function, but it seems not to be an array formula... Any other ideas?

Thanks!

Lots of great help here: Andy Pope Charting Guru

And Here: John Peltier - Charting in Microsoft Excel