Since nobody has checked in yet, i'll tell you what little I know.
The System expects to see a certain amount of power being used by that lamp circuit. If a lamp burns out, less power is being drawn and the system sees it, and assumes a lamp burned out.
My first thought would be to trick the system. It may not be a "pure" solution but it should work.
For example, install your new LEDs as usual but hook up the original lamps somewhere in the circuit.. maybe on the wiring inside the trunk where the lights will be on but can't be seen from the outside..
The LEDs draw very little power (as far as i know) and their addition won't overload anything .. and the system will see "at least" as much power being used as it expects to see, and it won't know the difference.
An alternative would be to add a resistor instead of the original lamps. However resistors get hot.. as much power would be 'wasted' by that resistor as is used by the stock lamps, and the lamps do get hot. The resistor's ohms and it's wattage rating would need to be carefully and correctly chosen.
this is just off the top of my head and a little bit of thought might result in a better, cleaner solution. Personally, i'd much perfer to work around the existing system than attempt to get deep into it and change the way it normally acts.
