Picasso - Custom RequestHandler doesn't cache images on disk

I need to load and cache images from some service. In example there is no such a service but it shows what I want to achieve.

My problem is that images aren't cached on disk. There is no usual folder /data/data/myapp/cache/picasso-cache.

How can I access cache from RequestHandler. It is even possible or it will be better to write custom Downloader?

RequestHandler

public class CustomRequestHandler extends RequestHandler {

    private static final List<String> PATHS = Arrays.asList("http://somelink/someimage1.png",
            "http://somelink/someimage2.png",
            "http://somelink/someimage3.png");

    private Iterator<String> pathIterator = PATHS.iterator();

    @Override
    public boolean canHandleRequest(Request data) {
        return data.uri.toString().contains("custom");
    }

    @Override
    public Result load(Request request, int networkPolicy) throws IOException {
        if (!pathIterator.hasNext()) {
            pathIterator = PATHS.iterator();
        }

        Bitmap bitmap = downloadFullFromUrl(pathIterator.next());
        Result result = new Result(bitmap, Picasso.LoadedFrom.NETWORK);
        return result;
    }

    private static Bitmap downloadFullFromUrl(String imageFullURL) {
        Bitmap bm = null;
        try {
            URL url = new URL(imageFullURL);
            URLConnection ucon = url.openConnection();
            InputStream is = ucon.getInputStream();
            BufferedInputStream bis = new BufferedInputStream(is);
            ByteArrayBuffer baf = new ByteArrayBuffer(50);
            int current;
            while ((current = bis.read()) != -1) {
                baf.append((byte) current);
            }
            bm = BitmapFactory.decodeByteArray(baf.toByteArray(), 0,
                    baf.toByteArray().length);
        } catch (IOException e) {
            Log.d("ImageManager", "Error: " + e);
        }
        return bm;
    }
}

Usage:

Picasso picasso = Picasso.Builder(application)
                .addRequestHandler(requestHandler)
                .build();

picasso.load("custom").into(imageView);