How add lines and shaded areas to an SSRS chart

I have created an SSRS line chart using Report Builder (version 15.0.900.71). I would like to indicate error limits for report values by adding two diagonal lines to the chart (upper left to lower right corner of the chart, and upper right to lower left corner of the chart) and shading the upper and lower triangles that result from the intersecting lines. Is there a simple way to accomplish this in Report Builder?  If shading is not possible, is it possible that only the lines can somehow be incorporated into the chart?  I tried creating two datasets (one for each line) to reference in the chart but notice that an SSRS chart can only be associated with a single dataset.

Any insights would be appreciated.

Thanks, 
Chris