you have 2 options for now, with the current firmware. I plan to propose a more universal solution in the next version.
On trick is to use the outputs of the drivers, the L+ pad on the CEx and CF main driver (the CF also has the shimmer pad, which is connected physically to the L+ pad of the power driver).
Connect the L+ pad to the anodes of a *common cathode* RGB accent led, and get the cathode return to some negative on the CF (not on the CEx). Each anode of the RGB accent must have a small resistor, calculate the value as indicated in the CF manual (wiring a progressive power on indicator).
That will give you an accent that mirrors both behavior and color of the blade, but only when it on.
The other solution allows you to have a the accent modes (blade mirror, sound mirror etc) applied at any time (including in idle mode, when the blade is off) and with varying schemes (normal, idle, lockup) BUT the color mix will be approximative and will only involve combination of dice (red, red+blue, blue+green etc).