Index: wp-includes/revision.php
===================================================================
--- wp-includes/revision.php	(revision 23859)
+++ wp-includes/revision.php	(working copy)
@@ -504,9 +504,28 @@
 	$post->post_title = $preview->post_title;
 	$post->post_excerpt = $preview->post_excerpt;
 
+	add_filter( 'get_post_metadata', '_wp_preview_meta_filter', 10, 4 );
+
 	return $post;
 }
 
+/**
+ * Filters post meta retrieval to get values from the actual autosave post,
+ * and not its parent. Filters revisioned meta keys only.
+ *
+ * @since 3.6
+ * @access private
+ */
+function _wp_preview_meta_filter( $value, $object_id, $meta_key, $single ) {
+	global $post;
+
+	if ( $post->ID != $object_id || ! in_array( $meta_key, _wp_post_revision_meta_keys() ) || 'revision' == $post->post_type )
+		return $value;
+
+	$preview = wp_get_post_autosave( $post->ID );
+	return get_post_meta( $preview->ID, $meta_key, $single );
+}
+
 function _wp_get_post_revision_version( $revision ) {
 	if ( is_object( $revision ) )
 		$revision = get_object_vars( $revision );
Index: wp-admin/includes/post.php
===================================================================
--- wp-admin/includes/post.php	(revision 23859)
+++ wp-admin/includes/post.php	(working copy)
@@ -1278,6 +1278,18 @@
 		$new_autosave = _wp_post_revision_fields( $_POST, true );
 		$new_autosave['ID'] = $old_autosave->ID;
 		$new_autosave['post_author'] = $post_author;
+
+		// Auto-save revisioned meta fields too.
+		foreach ( _wp_post_revision_meta_keys() as $meta_key ) {
+			if ( ! isset( $_POST[ $meta_key ] ) )
+				continue;
+
+			// Use the underlying delete_metadata and add_metadata vs delete_post_meta
+			// and add_post_meta to make sure we're working with the actual revision meta.
+			delete_metadata( 'post', $new_autosave['ID'], $meta_key );
+			add_metadata( 'post', $new_autosave['ID'], $meta_key, $_POST[ $meta_key ] );
+		}
+
 		return wp_update_post( $new_autosave );
 	}