I am working on a small addition with a slightly pitched fiberglass roof. I believe you would call this a widows walk. The roof is only 5′ 0″ x 7′ 0″ and almost flat. The new addition is the same dimension , directly under the existing roof.There will be a new front porch roof with a 6″ pitch that rises about 2′ 0″ above the fiberglassed roof.This is a gable roof with the gable end finished in MDO and painted.The front of the FG roof gets a sloping wall with handrail and balusters above.The reason for the slope wall is to hide the view of the gable peak.The problem I have is the FG roof slopes towards the gable end, I could easily flash behind the siding and over the fiberglass, and the rain will eventuall go towards the eaves where I will install gutters.I plan to  use white aluminum coil stock for a flashing as the FG roof is white. Would silicone caulking under the flashing edge and over the nail heads work. I could fiberglass over the exposed flashing, but I am not sure if fiberglass over aluminum flashing wood be the best way. I appreciate any input

   Mike