this should of been discussed before he started the job.your plumber was not up front with you. I can understand that he does not have the proper equipment to scaffold that pitch. this roughing will not pass if the vents are not brought through the roof. what he should of done and I have done this in the past is cut the hole and run the vent up through the roof and left the vent flange for the roofer to install. but most likely your roof probably was all ready installed. looks as tho your going to have to call your plumber back and have him extend the vent through the roof and then pay to have the roofer come and install the roof flange. This happens a lot when home owners want to be there own G.C. the sub's take advantage of the homeowners inexperience. Sorry. this could of been avoided by agreeing to pay the final payment when roughing inspection was approved. sorry for your ordeal!. Bob.