Ok, this turned out simpler than I thought. I had to ignore the provided functions and just act directly on the content editable div. I also have to use the bookmark as I can just store the bookmark string in a hidden field.
I should also mention that this will most likely only work in IE.
var bookmark = null;
function RestorePosition() {
$('.nicEdit-main').focus();
var range = document.selection.createRange();
range.moveToBookmark(bookmark);
range.select();
$('.nicEdit-main').focus();
}
function SavePosition() {
$('.nicEdit-main').focus();
bookmark = document.selection.createRange().getBookmark;
$('.nicEdit-main').focus();
}