While working on moving breadcrumbs from data-vocabulary.org structure to schema.org struture, i used the descrption and example provided on http://schema.org/WebPage, but aparently things does not really work as they are supposed to.
If to take their example
<body itemscope itemtype="http://schema.org/WebPage">
<div itemprop="breadcrumb">
<a href="category/books.html">Books</a> >
<a href="category/books-literature.html">Literature & Fiction</a> >
<a href="category/books-classics">Classics</a>

and to paate it to Google Structured Data Testing Tool the result will come as
<strong>type:</strong> http://schema.org/webpage
breadcrumb: Books > Literature & Fiction > Classics

which is not quite what we need.
So, after some google found the solution on W3.org site and i believe it may be helpful to someone.
Here is an example that will work just fine:
<div itemscope itemtype="http://schema.org/WebPage">
<!--First chain-->
<div itemprop="breadcrumb" itemscope itemtype="http://schema.org/Breadcrumb">
<a itemprop="url" href="/category/books">
<span itemprop="name">Books</span>
<!--Second level of the first chain-->
<span itemprop="child" itemscope itemtype="http://schema.org/Breadcrumb">
<a itemprop="url" href="/category/books/classics">
<span itemprop="name">Boring classics</span>
<!--Second chain-->
<div itemprop="breadcrumb" itemscope itemtype="http://schema.org/Breadcrumb">
<a itemprop="url" href="/category/bicycles">
<span itemprop="name">Bicycles</span>
<!--Second level of the second chain-->
<span itemprop="child" itemscope itemtype="http://schema.org/Breadcrumb">
<!--Last element is not a hyperlink in html-->
<!--but it has a hyperlink in microdata markup-->
<span itemprop="name">For kids</span>
<link itemprop="url" href="/category/bicycles/three-wheeled"/>