I've signed over the copyright to IEEE so I think I've got to ask them before I put it there - that is a great point though, I'll see if I can drop it in there.
The usual way this works is, you retain rights to the preprint. That's what preprint repositories like https://arxiv.org/ are for. Talk to your advisor, if you have one; if not, the folk over at Academia Stack Exchange are probably familiar with the exact rules of that IEEE journal.
Is that how they do it, rather than you assigning rights to make copies, while retaining your own copyright?