Hm… I think that if I tried to transform it literally, it would be closer to どうして も. どうして is rather different since it’s usually used as a question meaning ‘why’. Also, technically, して is just a request form, because ください is implied, even if it’s more polite to actually say ください. It’s not the imperative. しろ (spoken) and せよ (written/formal) are the imperative forms for する i.e. the forms for giving orders.
Anyway, I went and did a search, because I was trying to figure out why the imperative is used in these hypothetical forms. It’s not intuitive to ‘order’ something when you don’t want it, right? Well, actually… this is apparently a form of the 放任用法 (‘non-interference’ usage) of the 命令形 (imperative). An example I found online said something like ‘imagine a spy in an enemy country who’s been caught, and who will be killed if he doesn’t reveal state secrets. He might say, 「殺すなら殺せ！」(“If you’re going to kill me, then kill me!”)’ The spy doesn’t actually want to be killed, but he’s expressing the idea that he doesn’t care what happens. It’s the same thing in the structures I mentioned earlier (like いずれにせよ). Also, it helps to remember that these expressions only make sense when used to describe something that hasn’t happened yet, which is rather hypothetical in and of itself.