Wordpress get posts with empty custom field
===

I have this query to get posts with custom field, which works perfectly.

    <?php query_posts('meta_key=version&meta_value=one');  ?>
    <?php if ( have_posts() ) : ?>
    <?php while ( have_posts() ) : the_post(); ?>
    // my posts displaying 

Now I wants to get posts which does not have meta_value to 'one' or does not have version meta_key set. I tried with empty strings 'meta_key=&meta_value= ' but it return all posts including which has meta_value to 'one'.

Thanks for any help
