Vinyl Fence Posts as Sewer Hose Storage - A few questions?

Well I don't believe that small holes will weaken the frame, as stated dealers and manufactures do it all the time to enclose the under belly.

If i were you I would use self taping #14 screws into the side wall of the frame. That following pictures are how I did mine. The 5" post will hold all the fittings, I also made it so it would open on both sides.









Even the 90 degree elbow fits!!