As an alternative to reposting entire manuscripts, I suggest using the "Quote" option and then snipping everything that didn't need attention. This method is widely accepted on critique sites. Another option is to snip as mentioned above and then change the font color for your suggested edits or comments.
Always clearly signal your snips, as:
Reader's comment.This text stays here. This text stays here. This text stays here.
snip
Reader's comment.This text stays here. This text stays here. This text stays here.
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Hope this helps.
LC