Index: comment.php
===================================================================
--- comment.php	(revision 13514)
+++ comment.php	(working copy)
@@ -1265,6 +1265,13 @@
 	$commentdata['comment_approved'] = wp_allow_comment($commentdata);
 
 	$comment_ID = wp_insert_comment($commentdata);
+	
+	// If a filter provided metadata, store it now that we know the comment ID
+	if ( isset( $commentdata['comment_meta'] ) && is_array( $commentdata['comment_meta'] ) ) {
+		foreach ( $commentdata['comment_meta'] as $meta_key => $meta_value ) {
+			add_comment_meta($comment_ID, $meta_key, $meta_value, true);
+		}
+	}
 
 	do_action('comment_post', $comment_ID, $commentdata['comment_approved']);