Excel 2003 - stacked column charts

[Graham Catto]

I am trying to generate a chart to compare 12 months budget and actual data. Each months data is made up of several values and I want to show these as a stacked column chart so that the relative percentages of actual vs budget can be compared (with actual on the primary axis and budget on the secondary axis). So far I have been unable to generate the chart with 2 sets of stacked column charts - I can get stacked column and line chart; column chart and line chart; etc. Can anyone point me in the right direction as how to create 2 sets of stacked column data in one chart?