Is there another way to specify the line/fill color? I have very similar problem, except the type of my series is also dynamic (stored as CartesianSeries), and setting the color of Border for LineSeries doesn't seem to change the line color.
Never mind, I realized that since I was saving it as CartesianSeries I didn't have access to fields such as Stroke. I am now simply checking for each type and casting it.
Edit: I got everything except for BarSeries fill working. How do you specify the color of the barseries?