Vent flashing

I am building a new powder room (toilet & lav) and I need to install a new 1-1/2" vent through the roof. The piping will be PVC. The roof is essentially flat (1/12 pitch) and is a roll roof (composition type sheets approximately 4' wide), with a silver reflective coating applied to reflect solar energy. I am thinking of using a roof flashing which has a galvanized plate, with a neoprene boot that is flexible enough to accommodate the low pitch. Similar to this:
I would using roofing cement, slide on the flashing, then apply more roofing cement, roofing felt around the perimeter, and more roofing cement on top. Does this sound like a good solution?

Dave

IT is probably your ONLY good solution.

Will Maryland let you punch an 1-1/2 vent through the roof? Up here we can't use anything smaller than 3"

We are not in the frost-closure area so it is my understanding that the 3" minimum doesn't apply.

Coming from custom home plumbing you are on the right track. Typically you do not even need the flashing with rubber boot, just a galvanized roof jack with mastic is how most roofers complete the seal possibly using torch down. Copper flashing and lead flashings are another option.