Runway Lighting

Hi Guys, I seem to be having a problem improving or in some cases putting runway lighting into my payware airports. I have followed the tutorial to the letter about adding the runway lights to the airports,after placing the file into the airports scenery folder i log on the airport and yes the runway is still in darkness or really poor lighting. I have no other problems about adding ILS etc to the airport,its just the runway lighting for payware airports,hoping you can point me in the right direction. With Thanks Gary.​