I am trying to format a column chart with overlapping columns
the goal is to 'fill' the budget box with income and expenses colouring/pattern.

the goal is to show Budget, income and expenses.
Budget is a hollow box with no fill (this bit works)

Am trying to set income and expenses as a pattern, with a fore-color and transparent background color.
I can not see how to set the pattern background colour as transparent or 'null'.

Questions:
1. can this be done?
2. if so, how?

thanks heaps