WPF toolkit chart axis styling

Hello all,

I am using the WPF toolkit chart controls and I'd like to show a Axis-Y with different colors.

For example, 0 uses orange, >0 uses red, <0 uses blue. Please check the attached picture.

I created 2 Axis-Y at left of the chart (-10~0, 0~10) , but they displayed side by side as 2 lines, not a single line.

How should I do to implement the effect like the picture?