Does anybody know if there is a way to increase the brightness of the display on the Modulus head unit?

Under strong sunlight, the darn thing is barely readable. There is mention of an LED Setting in the manual for the OPT settings. In summary, it lists 5 options which can be set, User 1,2 or 3, Stereo/Mono, Driver L/R side, Phone Mute/Audio and LED.

But going into details, they seem to skip right past it after talking about the Phone mute settings, no mention of the LED thing.

Thanks!