Hi Ashot Golovenko, one viable work-around for the time being would be that you add doc value fields required for sorting add yourself from within your field bridge. E.g. like so:

document.add( new NumericDocValuesField( name + "." + lang.name() + ".count", info.getCount() ) );
document.add( new NumericDocValuesField( name + "." + lang.name() + ".views", info.getViews() ) );

We may implement a cleaner solution down the road, but it should get you going for now.