how do find DSO Avg in Combo chart

[#1]

Hi All,

          I need  to show  Net  Sales (Bar) , Net Collection (Bar) & DSO Avg (Line) in Combo Chart.

I have taken Net Sales & Collection in Bar but i dont know how to take DSO Avg in Line.

The same thing i have done in straight table but i dont know how to do it in Combo Chart ??

DSO formula : 

Avg Sales = Net Sales (3 months) / 90 or 91 days

DSO = Closing Balance / Avg Sales

Can any one help me.

I have attached my Application.

Thanks & Regards,

Antony.                                                    

[#2]

Can Any one Answer for the Above Query...