i would like to combine a bar chart and a stacked bar chart in one plot. how can i do this (i only found replies in the forum that it can be done but not how

here is what i have:
- one DefaultCategoryDataset
- containing 3 series of data
here is what i would like to see:
- series 1 shown as a bar
- series 2 and 3 shown as a stacked bar
thanx for any help/suggestions/ideas,
thomas