How to usemin external files using grunt-usemin?

How to download external files and to concat, using grunt-usemin?

<!-- build:js release/all.min.js -->
<script type="text/javascript" src="scripts/jquery.js"></script>
<script type="text/javascript" src="scripts/jquery.carouFredSel.js"></script>
<script type="text/javascript" src="http://cdn.domain.com.br/scripts/jquery.cycle.js"></script>
<script type="text/javascript" src="http://cdn.domain.com.br/scripts/jquery.slideshow.js"></script>
<!-- endbuild -->

And useminPrepare show:

concat:
  { generated: 
   { files: 
      [ { dest: '.tmp/concat/release/all.min.js',
          src: 
           [ 'web/scripts/jquery.js',
             'web/scripts/jquery.carouFredSel.js',
             'web/http:/cdn.domain.com.br/scripts/jquery.cycle.js',
             'web/http:/cdn.domain.com.br/scripts/jquery.slideshow.js'] } ] } }

The two last files don't add on my all.min.js because are external files. How to include?