I have this issue too. In my case, I have the Advance Animation ticked and the landing/taxi light are visible and illuminating the ground in external view, but they are still invisible in VC.
Interestingly, I turn on the switches for taxi and langing light while at gate just to see if it works. It didn't work in the beginning, but after 3-5 mins it starts lighting up the ground in VC. Moreover, it seems like turing off the DOME light will make it work instantly. I guess now I just have to land and taxi with dome light off
Hope this helps
Michael