The problem with the warning light is usually a bad diode bridge from my own experience. Yes, you can bypass it like the above post mentions. But the diode bridge can be replaced if you want it to work as it should. It's not that easy and even if i've fixed hundreds of them, i would still exchange it for a rebuilt unit at your local parts store. (got spoiled)
The light is used to excite the generator and it has to go off when voltage is supplied by the generator. So you'd have to manually switch the light off after the voltage is provided.