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>

</div>

</body>

and to paate it to Google Structured Data Testing Tool the result will come as
Item

<strong>type:</strong> http://schema.org/webpage 

<strong>property:</strong>  

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>

        </a>

        <!--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>

          </a>

        </span>

      </div>

        <!--Second chain-->

      <div itemprop="breadcrumb" itemscope itemtype="http://schema.org/Breadcrumb">

        <a itemprop="url" href="/category/bicycles">

          <span itemprop="name">Bicycles</span>

        </a>

        <!--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"/>      

        </span>

      </div>

    </div>