I've got custom top level links, defined via settings > menu, like this:
Link = Products link-type = custom, url = #, css class = nolink (changes cursor to default arrow)
So the output is as follows (simplified for clarity)
<li class="nolink"><a title="Products" href="#">Products<span class="sf-sub-indicator"> »</span></a> <ul> <li><a title="Windows" href="/path/to/page">Windows</a></li> </ul> </li>
Since these aren't actual pages or posts, the plugin ignores them. So for item Windows that is a child of Products, the breadcrumb displays:
Home > Home > Windows
Home > Products > Windows
Also note that 'Home' is rendering twice.
I could just make some blank pages & link to them, but that's a Kludge. Plus I'd have to exclude them from searches, internally & externally.