I recently installed a 6" triple wall pipe thru my second story and into my attic. I need to go thru my metal r-panel roof the kit I purchased came with a part to be installed on a roof with shingles. I ordered a new piece (from duravent) supposedly for a metal roof it has a flexible maybe aluminum base. However I can't figure out how to install it Duravent will not tell me how to install it but they say I have to use it to insure the safety of my home. They say that I can't use a boot. Any thoughts?