How 2: Rear lights + brake lights?

[JoFreak]

Hi guys,
I'm trying to get some lights onto my Slash 4x4 but I'm having a few problems regarding the rear lights.
I want to use the same LEDs for the always-on rear lights and for the brakes.
Meaning they are dimmed all the time, and when I hit the brakes they are supposed to go to full brightness.

I found and read Brian's thread on using an old servo board and will do so.
But how do I manage that the brake lights turn to full brightness as soon as I hit the brakes and not just after I pushed the trigger at least quarter of the way?
And what do I need to do so that the lights stay on all the time, but visibly darker, when I'm not on the brakes?
Maybe with parallel circuits? One permanently on with a higher resistor and let the servo board switch the parallel circuit on, with a second resistor which, parallel to the first resistor, results in the lowest possible resistance for the used LED.
That should do the trick if can get the adequate resistors, shouldn't it?

I'm thankfull for any help you guys can give me.
I do have basic knowledge of ohm's law, how to calculate resistors and so on, but absolutely no idea on how this servo board works.