Combo Charts with independent data set.

[fawmi]

I would like to create a combo chart. The bar chart displays the numbers and the line chart shows percentages of changes. So lets say, if 1200 items are available in inventory, it is 20% of inventory. I want the bar chart to show the 1200 and the line chart to show the 20%.

Is there a way for me to use the combo Chart in a way that two datasets remain independent.