Pairs of values in Scatter Chart

[#1]

Hello,

I'm trying to create a Scatter chart using dimensions for the size of the bubbles. I would like to display two bubble sizes for each dimension, one showing actual size vs predicted size. I can produce this in an Excel chart but I don't know how to go on about this in Qlikview - See below. Coloured bubbles are actuals and black hollow bubbles are predictions.

I have tried overlapping two separate charts changing the Z value in each, but for some reason, the sizes of the bubbles in the hollow bubbles graps and the thickness is such that makes the overlapping fail. In the example above, the black hollow bubbles don't increase the thickness of the bubble with it's size.

I would be grateful if anyone could help.

Thanks

[#2]

This is what happens when overlapping both graphs modifying Z value: