I use Firefox, too, but not as "locked down" as yours. Interestingly, I (just for fun) tried to "Go Advanced" from "Quick Reply" and tried the paper clip icon. It did not work. So I tried the red "Reply" button and when that screen came up, the paper clip icon would work. I also tried "Quote" and the paper clip icon worked that way, too.
Janey - Neat people never make the exciting discoveries I do.