Changed grid row color in listpage form in ax 2012

Hi AX guys,

I need to change the  grid row's color if certain conditions are met. The usual solution for this is to override the formdatasource method displayoption(). However, the form is listpage type and the customization works only in the interaction class (AX 2012). How can i do this task in AX2012? I am trying to have the code below to override the displayoption method, but nothing happen.

[FormDataSourceInteractionAttribute('ReqPO', 'displayOption')]

public void reqPO_DS_displayOption( Common   _p1 = null,

                                    FormRowDisplayOption   _option = new FormRowDisplayOption())

{

//some code to do the coloring of grid's row;

}

Hope any guys from AX world can help me with this.