It looks like you are going to have to have to do something with this chunk:
I’m pretty sure what is happening here is that the rendered size of the anchor element is 0x0px. Anchors are by default inline elements, and with nothing inside except for an absolutely positioned element, it’s not getting any size to it and thus is unclickable. Firefox is being cool about it and understands what you are trying to do but IE isn’t. Perhaps you can tag on a unique class to that anchor element which you can use to make it display as a block and set a width and height to it, which should make the region clickable.