Hide or edit individual legend items

[MAVIE]

Hi all,

I have created a combined line and column chart, in which the column "Net Activity" have a custom color formatting to show when a value is below or above 0. However, after creating the custom formatting, the column legend shows the original color of the column. I have been unable to find a way to either hide the legend item or edit it to not show any color next to "Net Activity".  
In the very least would like to maintin the legend item for "Daily Average" line.

Any suggestion for how to do this would be greatly appreciated.