Douglas J Miannay provided this picture showing how he reused the perforated pipe that came with his original Oceanic standpipe kit.
A 1¼ to 1 inch slip reducer is placed into the standpipe opening of the Street-Ell. The perforated pipe fits into the reducer. Doug used a 1 inch threaded reducer on the bottom on the perforated pipe and capped it off with a threaded end-cap.