In case you want to do it and haven't seen how, go to > Journal Style > Customize Journal Style scroll down to nearly the bottom and set "Disable customized comment pages for your journal" to NO.
(Also, on a personal level, I am on DreamWidth under my old username - mara_sho - but the library filtering system apparently finds something offensive about the term "DreamWidth" (can't think what they might be assuming it is... no, really...) and blocks very nearly all pages there so I can't really use it...)
ETA okay, just tried to do that on a community and it didn't work. Hmm. Anyone have any suggestions for them?