drawing tick marks in grid line in flex

Question

Hi All,

I am drawing a line chart with 4 line series. Two of them have negative values and goes under the 0 line. I want only the grid line across 0 to be displayed. hence i used like this :

<mx:GridLines direction="horizontal" 
                horizontalOriginStroke="{originStroke}" 
                horizontalShowOrigin="true" 
                horizontalStroke="{blankStroke}"/>

By doing this I am getting only one grid line across '0'. But I am wondering if I can put tick marks corresponding to the horizontal axis in this grid line. I tried many ways, but am stuck up there.

thanks in advance, Cheers, PK