You'l need to remove the dome light, and the plastic trim that holds the roof liner card in place, but be careful, the plastic can easily crack and break..
I forget the proper name of the stuff, but something like Qwick Grip, or Kiwi Grip, or something like that, paint it on with a brush, or spray it on, if you can get your hands on a spray gun and pot with the right nozzle, and air compressor.