leaking sun roof

[Ruck]

Sitting in N. Central Pennsylvania watching Irene Rain, little wind/gusts. Water dripping in at the sun roof/dome over the shower stall. Question; can the white plastic trim be taken down from the inside? I figure that if I can take it down, and seal from the inside as well as the outside, that should take care of it. Is there some sort of gasket under it, and what type of sealant should one use, inside and out? Thanks for the input.
Travel safe!