Bar Chart Show null values

Hello guys,

     This might be something quite easy, but I haven't been able to think it out.

I want to show on a bar chart, all the days from the month, and then when I select some of my employees, i want to see the days he was working, as well as the days he wasn't working ?

I have checked Include zero values in both places, under the Dimension tab, and under the Add-ons tab?

Any Ideas?

Thanks in advance for the answer ;-))