Haven't tried this with a 'nolink' entry yet, but in both the opening and closing tag for the separator element (as chosen in admin), an additional class definition gets added... i.e.:
<li class="leaf separator-li"><span class="spanSeparator" class="separator">&nbsp;</span class="spanSeparator"></li>

I used "spanSeparator" as the class name and a space character as the separator (since there's an image used as the actual separator). Not a showstopper for functionality since it does work, but it causes all the associated pages to fail w3C validation and it was a pain to track down the css errors to get it themed with the 2 conflicting class names.